One thing you may want to look at is your browser logs to see if any (how many) of your users are using alternate browsers.
I am on 1280x800 (wide screen laptop) and on FireFox, I am getting a terrible screen scroll.
Screen grabs for IE and FF are attached.
Ah, thanks for showing me that! That would be vBindex 3.0. Know of a code-friendly portal system? Firefox doesn't like incorrect HTML because it runs on Mozilla, when IE sees it perfect.
As for the other community, though they give great tips (and it looks like a great community), most of that is stuff I've been doing for.. ages. o_O