I've been wearing a 16 or XL at weights between 209lbs (highest weight) and 190-ish (3yrs ago). Weird that 20lb range has me in the same size!! I was in a 14 from about 175-190lbs, and a 12 from 160-175 way back when.
Before that, I was still growing heaps, so who knows.
Ideally, I'd like to be about 160 and in a 10 or 12. I just want to shop at "normal" stores again, and with my height and build, 160 is a nice athletic shape.