As far as seasonal goes, I like the more natural types, like poinsettas, or cardinals, or pine trees for Christmas. Last year I bought some fabric that I *thought* I liked, until I got it home. It was printed with Christmas ornaments and absolutely ugly at home (but strangely appealing at the store). Buying stuff like that has taught me to think, and think, and think some more before buying.
Oh, and I don't like Halloween fabrics, don't know why, just don't!