I've already named a bunch of stuff in past test music threads, but why the hell not...
One of the best recordings I've heard is Al DiMeola's "Kiss My Axe" (LP or CD... Both are fantastic). Pat Metheny's made some great jazz/jazz-fusion recordings as well (like the live one from the early '90's called "The Road To You" and also the old 1978 Pat Metheny Group debut, which is awesome on vinyl... CD's good, but the original LP blows it away).
Classical is usually a good choice. The old CBS Great Performances CD's from the mid '80's are worth grabbing. And Deutsche-Grammaphon released a ton of great classical LP's in the '60's that sound incredible on a good system. RCA had their Living Stereo LP's, which also sound incredible. I prefer analog recordings though. I've never been much for digital classical (Not the big orchestra stuff at least... I've heard some good digital quartet/quintet stuff that sounded good though).
Dire Straits' "Communique" and "Love Over Gold" sound great on a good setup. I never liked the way "Making Movies" sounded, and I wish "Brothers In Arms" was an analog recording (It could have sounded so-much-better IMO).
Basically, with CD's, the key is to look for well-recorded music on uncompressed CD pressings (A lot of remastered reissues were compressed to the gills, which has a HUGE impact on the sound... Do yourself a favor and download the Dynamic Range Meter... I use the one for Foobar, and I use it all the time to check the dynamic-range of CD pressings I have... Comes in handy, especially when I have multiple pressings of the same album/recording). And in general, the best-sounding stuff tends to be recordings with a small number of instruments and no overdubs. When you get into 16 and 24-track recordings (or even more tracks than that with today's music), the music tends to sound less and less three-dimensional (the more tracks there are), although there ARE many great-sounding 16 and 24-track recordings. The old, early-stereo recordings were usually done with a small number of microphones and without any overdubs, and that's why they sound so-alive and 3D. It depends on the style of music too. Jazz and classical usually sound better than pop and rock recordings, though every genre has it's exceptions. Get to know the best mastering engineers (Steve Hoffman, Kevin Gray, Barry Diament, Bob Ludwig, etc., although not Ludwig's post-millenium mastering work... He started brickwalling once the Loudness Wars got into full swing). The mastering engineer has as big an impact on the sound of an LP/CD as the producer does, and yet most people don't have a clue. I obsess about this stuff, but for damn-good reason.
I pretty-much listen to anything nowadays when it comes to showing off my system (like the vinyl-rip of AC/DC's "Powerage" that I'm playing right now). After 3 years of trying to find the right sound, I seem to have reached one of the higher summits of hi-fi synergy. EVERYTHING sounds great now, even the stuff I used to specifically-avoid in the past. I love it. I finally have a system that can make OTHER audiophiles go, "Damn, that sounds good"... I thought I did before, but now I can see/hear where things weren't quite up to par... especially in the upper-bass, which was a bit boomy with my old speakers (No more boom anymore... No more blur either). It's a great feeling.
Just stick with 1st-pressings (usually from the country of origin) and you'll do well, but it helps to learn as much as you can about LP and CD pressings. The Steve Hoffman forum is a great place to learn that stuff. There's also the mono vs stereo issue, but I won't get into that here. It depends on the recording as well as the individual tastes of the listener.
*EDIT* - I'll throw another one out there just in case the OP is a hard rock fan. The German LP of Accept's "Balls To The Wall" is one of the better hard rock pressings I've heard over the years (I assume the US LP is decent too, but I haven't heard it). Great bass. If your speakers have some hard-hitting bottom-end, this album will show it off well... AC/DC's "Back In Black" and "For Those About To..." (Wharf) are both fantastic on vinyl (For AC/DC on CD, the Japanese 2nd-pressings and the Australian 1st-pressings are both great). Classic Bob Ludwig mastering at it's best. He used to be THE GUY back in the day, but sadly he caved in to the pressure from the label execs to "punch things up a few notches").