The genre I read the most would be shoujo, I like the fantasy or gender-bender settings most, but normal romance works well too ^^. I like it most when the main heroine has strong character or is strong physically too (like Bia in Crazy Girl Shin Bia or Tsukasa in TCP), I dont really like the whinny clingy type of heroines much, but then each rule has an exception.
I do like reading shounen from time to time too (like Kuroko, Prince of Tennis, Hunter x Hunter), mostly adventure and sports for shounen I guess. Next in line would be BL, it's nice and refreshing, especially oneshots or 1 volume stories ^^. Well, there were few seinen (for example Kingdom) and josei titles I liked too (can't recall any titles).
So those would be my favourites, but there are always exceptions, mostly because it depends on story ^^.