Pretty much any kind but Death Metal (I'll spare my reasons why because I know I'll get flamed. *), Country Western (Ruins classic country

), and Modern Jazz (Also ruins the original genre. Modern Jazz is just elevator music.) and kind of Rap. (I use "kind of" because there are a couple Rap Songs I like and I like Gnarls Barkley, although I consider that more experimental really :\)
I guess if I had to put any genre up high though, it would be Psychadelic Rock. The Doors, Pink Floyd, The Peanut-butter Conspiracy (You get the worlds tastiest cookie if you know this band), Jefferson Airplane (NOT Starship

), etc. etc.
I also really like metal, mostly the "classic" kind I suppose (Stuff like AC/DC, Iron Maiden, you get my point) though there are a couple modern bands like Lacuna Coil who are awesome. While I won't list J-Rock/J-Pop as an extremely high genre for me, The Pillows are one of my favourite bands evar (Even seen them live 4 times, three times in Japan, once in California during their brief "The Lostman Goes West" tour that was in California/Mexico.) and Ayumi Hamasaki is probably my guiltiest pleasure in music. I also like D, and while these two following people are composers rather than "bands," I also like Akira Yamaoka (Best known for his Silent Hill sound tracks) and Yoko Kanno (Best known for scoring shows such as "Macross" and "Ghost in the Shell: Stand Alone Complex," the latter being my favourite work of hers.). I also love Classical music, whatever genre that Voltaire fits into (They call him "Irish Goth," "Goth Parody," "Dark Cabaret," "Modern Cabaret" and other confusingly vague genres. I just call him a funny and talented man with a violin [and violins are awesome.]), and industrial (Nine Inch Nails, The Wench, etc.

). While people constantly tell me their "progressive" and other people constantly tell me they're "alternative" I also really like Red Hot Chilli Peppers.