Swell opening post. I've so far pretty much shunned streaming audio despite having had broadband for several years. Maybe I have to reconsider that soon.
Re music and GC2, the main things I want are a lack of obvious lyrics and some sort of "spacy" quality.
I use iTunes (despite not owning an iPod and not wanting one). I like it because the combination of their decent library interface and the "smart playlist feature" lets me have a meta-list I call Game Time. I feed it mostly from supporting smart lists based on genres (dub, ambient, etc.) with some lists for specific artists such as John Holowach, who has plenty of free stuff up on the
Internet Audio Archive.
Other artists I like for game time include: Bill Lasswell, Swayzak, Thievery Corporation, Mad Professor, Stereolab, Boards of Canada, The Higher Intelligence Agency, Jah Wobble, Funki Porcini, Legion of Green Men, Lee Scratch Perry, Mouse on Mars, The 462nd Zinnias, Kruder and Dorfmeister, Loop Guru, Basic Channel, Massive Attack, Sly & Robbie, Messian Dread, Amon Tobin, Swag, and Mr. Scruff. This list is neither complete nor rank-ordered.