Tyler,
To do weddings, you'll need at least a 20D, if not a 1-Series body. You'll also need some faster mid-to-long glass to go with that. The 80-200/4.5-5.6 will be unusable at most weddings (basically anything indoors) due to the lack of light. I'd also argue that if you're doing a wedding yourself, you need two bodies.
I know the XT is an improvment on the DRebel, but as far as AF performance goes, the 20D and 1-Series bodies annhilate it. Ideally a 16-35 2.8, 24-70 2.8, 70-200 2.8 and a few faster primes would be good with a 1D/20D pair. However, if you've been doing well with the lenses you have now, more power to you. I'd say that the 20D would be a good buy.