I used to, but I have read quite a bit on this site since, and it appears (from a scientific standpoint) that basting doesn't really add much flavor unless it is highly concentrated and applied with much diligence, per Kevin. Plus, from personal experience, I like a very crusty bark, and basting will slow that formation down quite a bit. If anything, I'll add a bit of sauce after pulling (pork butt) or just rely on the natural fat and juices and proper cooking to keep moist (brisket).
For ribs and chicken, I'll apply some sauce on at the end, but not during the vast majority of the cook.