Les Claypool's Frog Brigade - Purple Onion
Agreed.
Some stuff to add:
the Mars Volta - Deloused in the Comatorium + TREMULANT (their first EP)
MFDOOM - Doomsday
Madvillian - Madvilliany
At The Drive-In - Vaya (1999)
I was going to mention DangerDoom - The Man and the Mask.
I like anything with MF Doom though.
Here's some good ones:
The Wrens - Meadowlands
Broken Social Scene - You Forget it in People
Edan - Beauty and the Beat
The National - Boxer
Saint Etienne - Tales From Turnpike House
Elliott Smith - From a Basement on the Hill
Flaming Lips - Yoshimi (mentioned by others)