I like the look of this theme okay, and I like the forum links at the top. But there is behavior in this forum/theme that I don't like. Most SMF forums I visit, I can use my forward/back buttons, but this always seems to reset the page for me. So when I'm scrolling down a forum, each time I visit a topic and return, I'm at the top of the page again. I have to keep scrolling back down to find where I left off. Another thing is that links in messages don't open up new windows. I can right-click to get around that, but because of the forward/back thing, I tend to open windows in a new tab frequently.
Dunno if this stuff is just me or not. I use Firefox 1.5 & 2.0 on several different systems with the same behavior.
One thing I'd love to see is a "Show unread posts since last visit" option that I see on most SMF forums. That makes it SOO nice to read posts from all the forums that are new since your last visit. You don't have to click on each forum to find posts you might be watching. Something like this could also increase activity in the slower forums, as a topic may catch someone's eye who doesn't normally view those forums.
Just some thoughts.