I just created a background image for use with the BB Dimension Icon theme because I got sick of waiting for something decent to come out for the 8800. It works pretty nicely for me and is nice and clean. I'm not a huge fan of the icons in Dimension but it's the best I've been able to find without creating a theme myself, which I have zero desire to learn/do. I use BB Clarity font set to 7pt.
Incidentally, I saw on another forum someone mention that the Cingular theme is the best - I agree, but the problem is that you can't change the background to get rid of the clouds on top and bottom of the screen. Yes, you can change the background image to something other than the clouds but it only fills the center space and you're stuck with the cloud borders. If anyone knows how to get around this I'd appreciate the info because I'd love to go back to that theme with the same type of background below.