Honestly, I saw Zac Effron(sp?) on the front page and turned tail and ran.

However, I went back. Just off the top, the first thing I noticed... your registration form does some error checking, which is good, but if it catches an error, all my old input vanishes. So I can't review what I entered and change it, I have to fill the form out again entirely.

Another thing you may want to block if you plan on adding forums or any inter-user communication of any sort - I just signed up for an account with the name "admin". If you had forums, or a private message system, etc, I could now very easily social engineer information out of other users. You should consider a list of banned usernames.

Third thing, I signed up with an invalid email address. I don't mean one that doesn't exist, I mean it didn't even conform to name@domain.com guidelines. May want to add another check in there for that.

Design wise, I like blue, so all good there. ;) Sorry to be critical on your user authentication, but you did ask for a review.
-m