I use 1024x768 as I like it for reading, graphics editing etc.
And with 1024x768 (which plenty people still use) right sidebar doesn't fix, try to save few pixels horisontaly so it will match 1024.
Firefox 3.6.3 @ 1024x768:
Also post preview thumbs are 75x75 px, I think 100 to 120 px with match that and it will be more eye catching, especially for new visitors. So there'll be less traffic bounce (people that leave site in less then 5 seconds).
Also I would make smaller header so there'll be more visible content without scrolling, attracts more new visitors.
Sites logo is cartoon, and site even doesn't have that category, so it doesn't match and is bit confusing. I would pick something that match best sites content, I would pick some hot teen with big natural boobs so it will attract or something else, but it should attract most of the porn surfers taste.
Categories should have slightly different line up, You got 3 lines, I would place common categories in first line, amateur, teen, lesbian asian.
And place categories that are loved by part opf pornsurfers but some part don't like them in second line Tranny, MILF, Grannies .....
GL in progress.