I've been in a prog-metal/technical-metal mood the last few days.
Spiral Arcyhitect - A Skeptics Universe
Incredible technical ability, very complex time signatures and rhythms, but no loss of melody or emotion (and clean vocals!).
The best technical metal CD ever? Could be...

Followed by the one of the most drop dead displays of unearthly musicianship available!
Electrocution 250 - Electric Cartoon Music from Hell
