I always notice when a page isn't quite vertically long enough to fill my entire browser. Examples are the users page (viewed on 1280x1024) but there are plenty more. I think Stack Overflow would benefit by changing the way the footer works in some way.
It might work to extend the grey footer color to the bottom of the screen OR stick the footer to the bottom of the screen so we don't get white-space after it.
I'd be interested to hear opinions.