Does anyone have any reccomendations for a zoom lens for my Canon Rebel XTI?

If you don't want to spend a lot of money, I'd suggest going for a Sigma lens -- I have a 24-135mm that works fairly well... it will extend to 135 while it's on my neck because the gearing isn't fantastic, but the picture quality is great and the cost is low.

I'm a big fan of the Tamron 28-200. Great range, reasonable price. Try it out!

Try before you buy. If you can, go to a quality camera store and rent the two lens you are considering and rent them at the same time and take pictures of the same subject with each lens so you can compare features, optic quality, color saturation etc. then buy the one you like best.