I've been throwing around the idea of replacing my f/4 IS version with the f/2.8 IS version. I still haven't decided, but I did find the f/2.8 IS version for $1500 at http://www.allenscamera.com/
after rebate. Prices aren't displayed online but you can call and get them. Seems to be lower than the usual big boys, so I thought I'd share for those looking. 

