It definitely depends on my mood & the weather.
For me, I like almost everything, so for me it's really a matter of what I DON'T like:
My least favorite style is American Amber. They tend to be over-hopped, cloying crystal malt bombs to me.
I am not a fan of Light American Lagers, though believe it or not I actually prefer to judge light lagers of all types. I am simply burnt out on IPA, so I tend to avoid them now. I'll still enjoy one maybe once a month, but that's the limit on them for me.
Otherwise, Gueze, German Pils, Helles, APA, American/Oatmeal Stout, Vienna/Marzen, Flanders Red & Brown, Berliner Weiss, and Blonde Ale are high on my list, though I really do like just about everything.