Spring and summer colors that pop. My house is very neutral but I lean towards pink, orange, aqua and greens for my fabric. If I can mix a black or silvery grey in I'm super happy. I love the snowmans gathering line and the more non traditional Christmas colors for winter like cream, midnight blue and a richer tan for fall and winter.
My fabric shopping tends to go with seasons. I noticed when the weather changed I changed my fabric preferences. One day I want to make a quilt out of bright paisleys and one out of plaid. Those are my two favorite patterns.
One thing I do not buy at all is batiks or purple. They just don't do anything for me at all.