I'd say "post it here," but you should think about who (and what) you're aiming for.

Hackers tend to focus on things like algorithms and blocks of text and whether you used a JPEG when you should have used a PNG.

If you're aiming for the mass market, your friends may provide more helpful feedback. They can point out obvious usability problems in seconds... just sit them down in front of your site and have them talk you through it.