The Specialist Fan is that guy (or gal) you know where when you have a question about an artist's discography, you immediately think to go to him (or her). This is the person who owns music by any number of artists in any number of genres, but there's usually one artist much more strongly represented. If you want to know what album a song was on, you call him. If you want to know which album to recommend to a certain type of person, you call him. And when you're Christmas shopping, you don't even bother to try to find something by that artist to give him.
Now, in my group I know Specialists in Kid Rock, Bruce Springsteen, Van Halen and KISS. This isn't to say those are the only artists those folks know, but they're their specialties. If I'm looking to know about any of those artists, I know where to go. My wife isn't really a Specialist Fan, though there are some artists whose discographies are well-represented in her library, including the Dixie Chicks and Sugarland. I've thought about trying to score her some of either's pre-breakout recordings, but they fetch quite a bit of cash on eBay these days. Plus, she's gotten into eBay and uses my account, so there's no way I could keep it a secret from her long enough to surprise her.
I happen to have three Specialties: Garth Brooks, Waylon Jennings and George Strait. I own literally every recording released by Garth and Strait, down to Garth's duet with Kent Blazy of "If Tomorrow Never Comes" from Blazy's Have Guitar, Will Travel album and Strait's reading of "Red River Valley" from The Horse Whisperer soundtrack. Waylon's a little harder to be complete, having recorded since the late 50s, but I have all his CD released albums save three older, out-of-print ones and a spattering of his miscellaneous recordings. Recently, I found the soundtrack album to Sesame Street Presents "Follow That Bird" which features Waylon singing "Ain't No Road Too Long" with several Muppets; it is currently the gem of my Waylon library. Given that Garth has recorded much less than Strait or Waylon, and given that my Waylon library is still very lacking, I suppose that means my top Specialty is Strait. That's cool with me.
Now, I mentioned the discouraging part about shopping for the Specialty Fan and actually trying to add to his or her library. This can actually be a fun thing to try, because you have to do two things: 1) you must discover what your friend has and 2) you have to research the artist's discography. You don't necessarily need to earn a major in Kid Rock, but you do need a minor if you're going to attempt this. An easy way of going about it subtly is, of course, to come to your Specialtist Fan friend with the question of what recommendations they would make of the artist from their own library. Get a Specialtist Fan talking about what they have and you'll not only find out what they already have, but they'll eventually namedrop something that's missing that bugs them not having.
One place to start with your research is Wikipedia, a website I rank in the top 5 best websites developed yet. You can learn practically everything about an artist's discography from Wikipedia, including where to find out more! I usually don't advise starting with the artist's website, because they generally only list their album releases. Your Specialtist Friend already has all these, because this is where he started building his collection. Much more helpful to know are miscellaneous contributions the artist has made to soundtracks, tribute albums and the like. For this, if Wikipedia isn't helpful (or incomplete, as it often is), I suggest searching for the artist at a site like Amazon.com, half.com (an eBay subsidiary) or perusing a music download service like Rhapsody.
You may be tempted to use a download service like Rhapsody, thinking you'll buy a disc's worth of miscellaneous recordings and burn them to a disc for your Specialtist Friend. There are two schools of thought on this. One, your Specialtist Friend will be able to add all these stray recordings to his library, and they're conveniently collected on one disc, to boot. On the other hand, though, the Specialist Fan is usually a collector and prefers owning original, tangible discs. For the casual Springsteen fan, it might be a cheap thrill to have a disc that includes his contribution to the Philadelphia soundtrack; the Springsteen Specialist Fan would prefer to own the soundtrack.
Now, the nice thing about this sort of project is that the kinds of things the Specialist Fan may not already have in his or her library are the kinds of things that tend to show up dirt cheap in discount bins, BMG Music Service's clearance section or on a site like eBay. Not too many people are going to actually have to pay more than a couple of bucks for The Horse Whisperer soundtrack to give their George Strait Specialist Fan friend his recording of "Red River Valley," I'll tell you that much. And if they became a fan of George's after 1998, they may be completely unaware of that recording, because his website doesn't mention it at all (last I checked).
If I've just discouraged you from assembling a CD-R of purchased downloads of miscellaneous songs by the artist and you're not about to try to track down that many CD's and don't feel right just getting one or two CD's that have one or two songs by the artist, there is an alternative. There is an entire sub-field of collecting devoted to radio shows, and these can be found on eBay. Radio shows are generally produced to promote a major release by an artist, or they're part of a weekly series, like a hits countdown show or a biographical series. I personally have several of these, and as a Specialist Fan, they're the pieces of my library I like showing off to other fans of the artist.
The nice thing about radio shows is that they were never produced for mass retail, meaning that 1) your buddy never stood a chance of finding this at Best Buy or Wal-Mart and 2) your buddy will appreciate the relative scarcity of the item. For instance, Garth Brooks's Sevens has been certified 7x multi-platinum by the RIAA, meaning at least seven million CD's and cassettes of that album have been circulated. Meanwhile, the Sevens Interview & Cut-by-Cut Dialogue CD that was issued to radio stations to promote the album received a production run of maybe a couple thousand, tops.
The downside to collecting radio shows is that they can get pricey in a hurry. I once got in a bidding war for a Garth Brooks In Pieces World Premiere Interview CD that ran upwards of $50. I'm not proud of the fact I went that high, but I damn sure relish owning the thing. And if someone were trying to surprise me with something for my Garth library and went about it by asking me what kinds of things I had, it would be one of the first I would mention; such a person would then know not to bother getting in a similarly expensive bidding war for one. They would also quickly find out that I've been wanting to get my grubby little paws on Sevens World Premiere with Garth Brooks & Friends for a decade now.
One more area to investigate is a download service like Rhapsody or iTunes, where you can find free, exclusive material sometimes. For instance, Rhapsody has an artist interview series as well as Rhapsody Originals, where artists record exclusive, acoustic performances of a handful of their songs. If you're looking to surprise a Taylor Swift fan, for instance, not only has she recorded a few songs for their Rhapsody Originals series that'll cost you less than $4 to purchase, but she has been interviewed by them twice, and those interviews are free. On iTunes, you can search for podcasts, where you may discover a podcast series for your Specialtist Fan friend's favorite artist. Usually these accompany a new album release. Prior to the release of their Between Raising Hell and Amazing Grace album, for instance, Big & Rich had a seven or eight part podcast series, "Big & Rich: All Access." Also, Wal-Mart's download service has a lot of exclusive material as part of their Soundcheck series.
Now, these present an interesting dilemma because there isn't an original, manufactured release of these things. I suggest that if you go this route, you create a disc for each series you download. For instance, burn three Taylor Swift discs; one for each interview and one for the Rhapsody Originals performances. This gives the sense that each is its own release, which it is. CD-R's these days are practically nothing, so it's not like this will cost an arm and a leg. More importantly, be sure to create album artwork for the disc. Print up a thoughful, professional looking label for the disc and create inserts for the jewel case. Some services actually offer this with the purchase of downloaded material, and where you can get this, do it.
One final word of advice: Don't buy bootlegs. These are 100% completely illegal, they don't support the artist and, because of the way terrorists have financed their activities with bootleg DVD's and CD's, the government is (rightly) aggressively investigating these things. Not only should you not want to be investigated by the FBI, but you don't want to find out that the Christmas gift you bought someone helped pay for a dirty bomb somewhere. Stick with original, manufactured releases. Besides, as mentioned before, your Specialist Fan prefers original, manufactured material anyway.