Michael Cheddar wrote in post #10068969
To be honest. NO. I highly recommend The 85mm ƒ1.8 for what your doing. Just zoom with your feet. the 17-55 ƒ/2.8 on your rebel may not even come close to cutting it with your ISO at 1600 in most reception halls. If your thinking low light, go prime. fast. wide aperture primes.
Primes aren't for everyone, and the 17-55 will do fine. It covers wide to short telephoto at f/2.8 with 3-stop IS. Weddings have been done on 5D's with 24-70s for years, what's stopping an XT with a 17-55? Both cameras max out their analog gain at ISO 1600.
OP: You've done the weddings. You know what exposures you were getting. It's some simple calculations to find what exposures you will be getting with an f/2.8 or f/1.8 or whatever lens.
I suggest f/2.8 zooms and flashes. 17-55 IS and 70-200/2.8 IS is ideal. If you can't afford both right now, get the 70-200 IS first. Alternatives to the 17-55 are the Sigma 17-50 OS HSM, Tamron 17-50, and Tamron 17-50 VC.
If you want to try out primes to see how you like them, start with a Canon 35/2 or Sigma 30/1.4.
Flashes are important. When they are allowed, use them. Fast lenses and cleaner high ISOs will not make up for bad quality light, and shooting at wide apertures limits you because DoF is so thin.
If you don't make much of any money for your work, you should start charging more. I realize you've chosen the low-budget market, but do you plan on staying there? You have no obligation to do favors for those who think quality photography can be done for next to nothing. You should at least make enough money to subsidize your transportation and photographic equipment.