i could never name a 'best' - too much to choose from.
i saw phish a ton of times. my first show was in '92, but they lost me when they started attempting to be sappy and wrote the stuff like 'prince caspian'... pure vomit. so early phish i'm on board, later phish its 50/50 love it or hate it for me. but if i were to name my top 5 albums, i don't think phish would get listed. weird.
radiohead rules, as does pink floyd.
i gotta give it to the beatles - i have pretty much every album they have and they are regularly in the line up... but i prefer the later beatles versus the earlier stuff.
the chemical brothers - when i heard them i was pretty blown away. but again, it depends on where they were in their career, the early stuff has more quality to it than the later stuff IMHO.
been on a grunge kick lately and find a lot of soundgarden and nirvana getting into the line up. alice and chains gets an honorable mention just for the song 'again'.
janes addiction - i swear i used to listen to 'three days' every day my senior year.
james brown gets props for the funk and soul. the sex machine live album is just insane.