If the OP's still monitoring this post I have some good ones for you. At least to my ears I think these sound top notch.
Eagles - Hotel California
Queen - The Game
Queen - Night at the opera
Ryan Adams - Gold (4.0 or 4.1 can't remember)
Sheryl Crowe - Globe Sessions
Flaming Lips - Not into all their music but really shows off a 5.1 system
Beck - Sea Change
Elton John - Any of them
Dire Straits - Brothers in Arms
Pink Floyd - DSOTM (who doesn't like this?)
HDCD's (Can't say for sure how much difference vs Redbook CD but these ones sound really good)
Tracy Chapman - Telling Stories & New Beginning
Anything Ben Harper (very talented artist)
Anything Jack Johnson (I think Ben Harper got him started) Vinyl is even better
Check out the Drive-by Truckers for a southern style sound, pretty good.