The ones that can't be labeled and stereotyped like this thread attempts ...
I like things with a distinct style, and I expect games to have some sort of art style and deliberate aesthetic direction to begin with. That, surprisingly, isn't even the case all that often.
I can more easily say what I generally don't like: anything that tries to look realistic or even hyper-realistic. Apart from the fact that it's the most boring thing I can think of, it always ends up looking incredibly silly and off-putting, because UNCANNY VALLEY CUDGEL in your FACE.
Oh, and anything Anime makes my flesh creep and my blood boil in rage.