Looks good! I would add the same margins under your right widgets, the same size as the white space between both sidebar columns.
.art-contentLayout .art-sidebar1 div.widget, .art-contentLayout .art-sidebar2 div.widget {
margin-bottom:5px;
}
That should add 5px below all your sidebar widgets
Looks good for a first. Check out loading your images in a Lightbox, modalwindow, highslide, etc etc… When clicked on. I would also add random images all over the site. You have a lot of images use them! Put them in widget positions, also look into using WordPress built in thumbnailer, so the small image is the big one, forcing everyone to download a 2meg image when they are only viewing something at 50×50
Cheers
