I'm 5'7", 140 lbs, small busted, wear a small in regular shirts. But some of my workout tank tops are XL. In cycling tops I am anywhere from S to L depending on the cut -- even within one brand, I'm not a consistent size.

It's a problem for retailers, too, although I don't know if they know it. I rarely buy athletic tops online because I have no idea what size to get.

BTW right now I'm wearing a t-shirt that I got in the mid-90s on a trip to see Mets spring training games in Florida. It's a size large, but it's smaller than the "small" t-shirt I got at the Livestrong Challenge last year.

Oy vey.