I haven't upgraded my forums yet because i'm still waiting for the right skin. All your skins are great, but I'm still waiting for something like skinbox's "elegant".. not sure if you have something in the pipes with that kind of style or not.
I was just informed that there is no way for IP.Content to check for duplicate database entries. This is certainly an option which would be very useful to avoid repetitiveness. It would be a great idea to add an ajax option like you have for when choosing a username at registration ;)