Sorry for hijacking, but is it better to get a USM lens or one with IS considering one is shooting sports? Getting a lens with BOTH IS and USM is very costly.
The only IS lenses that don't have USM are the EF-S 18-55mm and 55-250mm. Those do not perform well in terms of color contrast, sharpness etc etc.
IS would not be needed unless you're talking about very fast sports (eg racing / biking) where you might want to pan your camera to achieve some nice effects.
To thread starter: For the normal sports like soccer, hockey, rugby, outdoor basketball etc, shoot at 1/500 (Use shutter speed priority mode ie Tv on Canon) to freeze action. Bump up the ISO if needed. For this shutter speed to be correctly exposed, you'd need a large-aperture lens of about f/2.8 or wider. Sometimes f/4 might do, but most sports don't take place under the burning bright sun, so f/4 might be a bit slow.
A 70-200mm will do for quite a number sports. A 1.4x TC converter is usually used to give more range at a cost of sharpness, contrast, CA and 1-stop aperture. Only recommended if you have a fast lens, if not, rent a fast lens with more reach, or rent a 200mm + tc converter.
At hand-holdable speeds of 1/500, there really isn't a need for a tripod / monopod. If you've got heavy lenses, you should bring one along just to save your wrist muscles.
(Always) Use a lens hood when shooting anything, even more-so under the sunlight. This will give you better contrast and more vivid color tones. It'll prevent you from touching the lens at the same time. Since specialised filters like CPL and ND filters won't be used to take sports (other than snow sports of course), there wouldn't be a need to fiddle with the front of your lens.
Hope this helps =)