60s - Hendrix
70s - The Clash
80s - Red Hot Chili Peppers
90s - Primus
00s - Tool

Tool is a band I could not have included because they straddle decades...2 albums each, and I don't have a strong preference one way or the other. I'm assuming you do, then.

-1940 : Mississipi John Hurt
50's : John Coltrane
60's : Rolling Stones
70's : Pink Floyd/King Crimson
80's : The Fall/The Smiths
90's : Death/Placebo
00's : TMV/The White Stripes

50's: Miles Davis, The Shadows
60's: Charles Mingus, The Beatles
70's: Black Sabbath, Funkadelic
80's: XTC, Gang of Four, Michael Jackson
90's: Refused, At the Drive-In
00's: Between the Buried and Me, The Blood Brothers

60's: Mothers of Invention/Zappa, Captain Beefheart and the Magic Band
70's: Genesis, Queen
80's: Rush, The Smiths
90's: The Flaming Lips, Bjork
00's: The Mars Volta, The Sound of Animals Fighting

Actually, Aenima is my favorite. However, I haven't been lucky enough to find any music this decade that compares favorably to my preferred time period of about '85 to '95. Most of my favorite bands' best releases are from the 1980s or 1990s. I considered Dinosaur Jr--even though they've only released two ablums--and I considered The White Stripes. But there just hasn't been very much music that excites me. Perhaps someday I can look back on this decade the same way I do of the alternative era of the 1980s...

60s: The Kinks, Bob Dylan, The Beatles
70s: The Clash, Led Zeppelin, Joy Division
80s: The Smiths, The Cure, The Chameleons
90s: Blur, Manic Street Preachers, Jeff Buckley
00s: Arctic Monkeys, The Shins, Fleet Foxes

oh, this is hard.
50's: Miles Davis/Chet Baker
60's: The Beach Boys/Love
70's: Steely Dan/Todd Rundgren
80's: Prince/Prefab Sprout
90's: My Bloody Valentine/Sonic Youth
00's: Wilco/Jay-Z

60's - Bob Dylan
70's - The Clash
80's - Bad Brains
90's - Lagwagon
00's - The Mars Volta

50's- Duke Ellington
60's- The Beatles
70's- Led Zep
80's- The Smiths
90's- Radiohead
00's- Roots Manuva