re: What Genre Defined the 2000's?

Depends what you were listening to. There several subgenres.

Rock for the 2000s: Alternative Rock - Subs would be Nu Metal, Post Punk Rock, some Post Grunge, Alternative Metal, Emo, Electronic Rock.


For Pop: Who gives a shite most of that sucks.
For Hip/Hop Rap: This is pretty big in 2000s. Not familiar with that many sub genres of this though.

Anything else: Meh. Who cares again.