I like it overall! There are some niggling issues, though . . . at least looking at it in FF.
The "GO" button doesn't line up with the search text box in both the footer navbar and sidebar.
The top navbar would look much better if it was expanded to the edges of the contentWrap div.
Add some margin to the bottom of the page so the vBSEO links won't sit flush against the bottom of the browser window.
I would increase the width of the forumlastpost and forumstats divs to make things look a bit better when the sidebar is expanded.
The Facebook Connect button in the header needs to come down a bit to align with the rest of the toplinks content.
The sidebar for the blog section contains a lot of white text on a white background. This is obviously undesirable.
I would replace all the default collapse buttons with the custom ones used for the forum categories.
Along those same lines, I would create custom tab collapse buttons for the sidebar, as the default doesn't fit the custom theme.
Again, these are all small issues, but getting all those little things just so will really give the theme a more polished and professional feel. Best of luck with the site!