JP,
My wife owns the original Canon 80-200 f 2.8. Brian is right, its a monster, but it's also pretty sharp.
My personal preference would be to buy an 85 f1.8 for the signifcantly closer (portraiture) focusing and lens speed and a smaller 200 f2.8.
My predjudice aside, many of the guys at my local camera store are into Canon and are bemoaning the fact that their 80-200s don't have IS. They claim you get a real 2-3 stop improvement on the low end shutter speed.
I think if you're inclined to do hand held shooting, the IS version is the way to go. You'll forget the price differential shortly after the purchase and be very happy with the improved functionally of the lens as the years roll on. IS seems to be a really significant step in lens evolution.
take care,
Tom