Hi
I like the use of photography on the top left and the colours. I found the outlines a little stark and I was wondering what titles you would have for people who are not logged in.
The navigation text seems inconsistent. That is, you have a "profile" and "private messages" link and a "log in" link. Perhaps it would be a better idea to have those options available when you are logged in only as you wouldn't be able to access your private messages if you are not logged in.
The curves don't seem to be parallel in the curve on the left - maybe if you made them parallel (that is, the same distance apart from one another) and made the outline of the font a white colour then it would fit better. At the moment you have soft edges for your curves and a strong black for your navigation.
I suggest that you have your navigation in text format in the way you can display how many private messages they have and it leaves room for expansion.
The "register" link seems to be out of alignment with the other navigation. You could also add a texture to the grey - perhaps even a fade out the bottom.