Only one critical thing ... *LINK*
Clay Home
>I'd say this - no matter what, do not get one that 'hangs' from your neck, get one that crosses the back, so the weight's on your shoulders. Hanging any weight at all from your neck is tiring.
I wear one whenever I'm in the shop, even though it's usually only over shorts and a tee. I don't find that the pockets' contents get in my way, I like having a few things handy (small square, tape rule, marking knife, etc), I also use the pockets for the brads and screws I'll need shortly, and the pockets are a good place for the iPod! I also like having one that's washable canvas - seems like leather would get grotty with stain spills, etc.
I can't remember the brand of mine, but it looks sort of like the one Rockler sells for $22 (link below), but without their logo. If you want, I should be at the shop within the next coupla days, I'll check the brand of mine.
Clay
Rockler apron