Since I like almost all types of tobaccos, it's a long story.
In English blends I look for the hearty smoky (and creamy) taste of Latakia and I want to taste Orientals too.
In aromatics, I like blends that are relatively dry, yet smoke flavorful all the way to the bottom of the bowl without getting too wet in the bowl.
In Virginia and VaPer blends, I look for body and natural sweetness.
In burley/Virginia blends, I like balance and depth of flavors, not a dominance by the burley.