I have a growing appreciation for Yongfook... I'm using his Sweetcron script (which is brilliantly executed), his other projects are also really well done. It's just him and it amazes me that he has time to pump out his own music.
Speaking of which, if you haven't heard this artist yet... you'd probably really like him. He was well known as a designer (iso50.com) and self-produced his own music, equally talented.
i definitely prefer repetitive or ambient, non-lyrical music. sometimes i'll even put on sleep-music albums
a couple albums in particular standout: * philip glass & ravi shankar - passages * kawabata makoto (of acid mother temple) - infinite love - i think this album is tuned to my brain's beta wave frequency. its like sonic ritalin * robert rich - somnium
for more energy i usually look to montreal. godspeed and silver mt zion always please. a little bit lesser known is "do make say think" who are one of my desert-island bands.
and sometimes, just sometimes, i just have to listen to dancey trance music. check out onnomon (who is also, by the way, my brother and an old timey hacker)
as a side note, i mostly use rhapsody for online music. its just straightforward and easy... well worth the monthly subscription fee. if only the site was a bit faster.
as far as free services go, i really like the spirit of last.fm but pandora's recommendations are consistently better.
Hit shuffle on that, and I have myself a killer well-mixed playlist in terms of variety, tempo, and genre selection.