"Best" is hard, as is "Rock", to specifically define, but here's several I think rate:
Tool - Aenima
Queensryche - Promised Land
Dream Theater - take your pick
Massive Attack - Mezzanine
Pink Floyd - Wish You Were Here (and several others)
Days of the New - both albums
Metallica - Master of Puppets (DCC)
Joe Satriani - Surfing With the Alien (MFSL)
Counting Crows - This Desert Life
Dire Straits - pretty much all of them.
Tori Amos, while probably not rock per se, has incredibly high sonics on her releases, as well. -Kirk