I had some reservations about buying a non-Canon lens, but at the recommendation of a few people here, I decided to bite the bullet and get the Tamron 17-50 f2.8. I shot a car I just finished building today. Its so amazing how much better this lens is than the standard 18-55 lens that came with my Rebel.
I only have to save up $2000 more to get my 70-200 f2.8 IS unit. 

It's an excellent budget 17-55





