Hey guys,
I am really new to this photography thing and was just wondering if anyone can help me with my choice of some lenses.
I have a Rebel XT and want to shoot mostly fashion and portrait.
Canon has a 24-70mm 2.8 lens that i think would be my best choice. Do i need a telephoto as well? I saw the 70-200 2.8 IS. Also, is it a good idea to have a 50mm 1.8? What uses would that lens be for? And lastly, would i ever need the 16-35mm 2.8 for shooting fashion?
Thanks for any help in advance.

I'm a big advocate of primes, but just about any Canon L glass is to be envied.  But if you are looking for a wide angle zoom, check out the 17-40.  Your best bet is really to rent them and see how you like the results.

And yes, the 50mm f/1.8 is the best value in the entire photography world.  Buy one.  Or two.

I agree with all of the above except that I think you might be better served by going with the 70-200 f4 instead of the 2.8. If you're shooting with strobes and don't need IS, it's hard to beat. It's about half the price and weight of the non-IS 2.8 and just as sharp (to my eyes at least). Great color and contrast and gorgeous bokeh.

Herb

If you want some nice lenses for cheap, try the Sigma 10-20mm 4-5.6 and the Tamron 28-75mm 2.8

Your choices so far are great. Perfect glass for what you're looking to shoot. I disagree with hjlamb about the f4 vs the 2.8 though. It's all about the light. The more the better, you can always crank down, but can't crank up higher than the existing f stop. Plus you option with a shallow depth of field is nice to have. One more prime you may want to add is the 85mm f.18 the L is a better lense, but not necessarily worth the price and does tend to be slower with the AF.