To answer the original post, the best tire for me depends on the time of year. When it's <40F, I put a high premium on flat resistance, so marathon pluses are my tire of choice. Flatting out when it is that cold (especially in the 20s) is not just sucky, it's potentially dangerous.

At 40+, I tend to go for lighter tires that are more fun. I haven't got a favorite at the moment. I'm liking continental grand prix four seasons right now, but I'm riding in the rain a fair bit.