By the way my forum is dofollow, so don't be afraid to drop a few backlinks in your signature and start posting. This site will have good PR by the next update!
I liked the overall style only thing which i felt lacking was that the top right corner looks pretty empty..are u planning to add ads later?
I don't want to put ads there because most normal banner Ads dont do well on forums because people visiting forums don't usually click ads and personally I think forum users get turned off by ugly banner ads. Thats what i hear anyways, that forums tend to get less clicks. So what I do is I integrate text link ads right under the folders and right above the individual threads because they look less like ads so more likely to get clicks. Its a great way to encourage clicks on your ads without it being a big glaring banner. Im adding them in a couple days when I get around to it.
I decided to follow your advice and I added a banner ad in that area instead of having the banner ad at the bottom of each thread. I also put my text link ads under some of the folders in the front and above each thread and folder index. You can see what the ads look like above each folder http://www.dogownerforum.com/index.php/board,3.0.html and above each thread http://www.dogownerforum.com/index.php/board,3.0.html