Your default style is very nice. I like the header a lot apart from that incandescently annoying flashing text at the top (which is also 200kb+ and takes a while to load). I don't like the pixel font in your header, it doesn't go well with it. Also you have a times new roman font above the login box.
Your header is really nice apart from those few things, content-wise on the default style it just clashes with the nice header! It feels overly cramped
also noticed ur running 35 queries on your main page, i would consider lowering that count as it probably causes alot of server load and database stress
I really like it, it's nice on the eyes. My only suggestion is moving the vote for us and the welcome box to the bottom. This is because I feel that the actual forums are the most important of site, but others like it at the top. If you move it to the bottom, I think it will feel less cramped. Great job!