I have a T1i using a 28-135 canon, i have been wanting to upgrade my body, but i also want to get a wider lens. You think it will be best to get this lens first and the save up for a 7D? Hopefully a year from now the price will even drop.
We're in a similiar situation. I'm hanging onto my Nikon D90 until the D7100 drops in price. I would say buy it since you'll get immediate utility out of the wider 17mm and faster f/2.8. At 50mm on your 28-135, it is probably already dipping down to f/4.5 or f/5.