All the usual caveats for preferences of specific bands and artists apply, but in general, here's my list:
Rock - 5 (favorites are too many to list... I like old rock and roll from the 50's all the way up to modern rock)
Hard rock - 5 (again like rock, I love hard rock too. Led Zeppelin, ACDC, Deep Purple and Blue Oyster Cult come to mind but there are many others. I guess Rush fits here too, and they're awesome.)
Jazz - 5 (I love jazz in almost all it's styles, though there's very little modern jazz that I like.)
Early Electronic Music - 5 (Gigantic fan of music that features early uses of synthesizers, oscillators, theremins and so on. I even like the kitschy "Moog" novelty recordings from the 60's and 70's.)
Post-Punk/New Wave/New Romantic - 4 (the music that helped formed my childhood tastes. Ultravox, Magazine, Wire, Visage, Gary Numan, etc. Heck I even like early Duran Duran.)
Metal - 4 (fan of early Metallica, Megadeth, Anthrax and Slayer. Also like some Iron Maiden and Judas Priest.)
Blues - 4 (gotta really be in the mood for it, but I am a fan of traditional blues. I also like blues rock.)
Electronic Dance - 4 (I'm a fan but can't listen to it all the time. Favorite period is from 1988-1993.)
Pop - 1-5 (varies wildly. Some of it I love and some of it I hate.)
Funk - 4 (I love the funk. Parliament, Funkadelic, Brothers Johnson, even jazz/funk groups and artists like Return To Forever, Herbie Hancock and Weather Report kick butt as far as I'm concerned.)
Art Rock/Glam - 4 (Roxy Music, David Bowie and Brian Eno)
Classical - 3 (favorites are Liszt and Chopin)
Psychedelic Rock/Pop - 3 (I'm a ****** for weird hippie music.)
Neo-Psychedelic - 3 (Black Moth Super Rainbow, Flaming Lips, Orange Alabaster Mushroom)
Progressive Rock - 3 (a genre with a wild variance in quality. Gong is one of my all-time favorites. In general, I also enjoy Yes, ELP, the Moody Blues, King Crimson, and some others.)
Disco - 3 (Some disco tracks are awesome and timeless, but a whole bunch of it was imitative garbage. The hot tracks are unforgettable though.)
Hip hop - 3
Bossa Nova - 3
Soul - 3 (varies wildly, but Gladys Knight, the Four Tops, Otis Redding... all great)
Country - 2 (I like very little country music, and what little I like is Johnny Cash, Loretta Lynn and a smattering of other stuff from the 50's-70's.)
Reggae - 1
Ska - 1
Ambeint - 1