I don't care how you do it... there are horizontal ads, and there are vertical ads. But the big block ad that is currently in use is the the worst.

Replace it with a tall, thin vertical ad along the right side, keyword thin.
Or, use a horizontal ad up top and allow the forum area to have the width of the screen below...

Or, if the block ad stays... then there's one solution. There are a number of pages where the impact of the block ad is not really that horrible. Until you get to the actual thread, once you get into the thread for a particular question simply remove the ad from that page view. Or, change the ad for the thread page view to a horizonal ad up top.

The current situation is pretty horrible.