I like...
Ska
Punk
Indie
Emo / Screamo (Not Hawthorne Heights, more like Hidden In Plain View, Brand New, or MCR)
Synth-Pop / New Wave / Electronic (they're all synonymous)
Alternative
Progressive Rock
Grunge (If you can call it a genre, it's basically like saying I like Nirvana and Mudhoney)
Thrash Metal (If you can call it a genre, it's basically like saying I like Metallica, Megadeth, or Slayer)