I do a lot of hand held sports photography, so were sort of in the same boat. Most of my kids'soccer/baseballgames start at 6:00 at night, so it isn't dark but dusk, especially towards the end of the game. Of course the B-Ball games are in doors. I should point out that I take all shots hand-held. I aso take a lot of indoor pics of the kids, birthday party pics, sunsets,etc... I guess what I'm trying to say is that these are all considered low light situations. I should also take a moment to tell you that I rarely use the flash unlessI absolutely have to. This is where the IS really comes in handy and will save a ton of shots. IMO it's a must! In broad daylight or if your going to use a tri/monopod it's not going to help you, so you can just flip the switch and turn it off. I also have an XSi and the lens I use for sports is an EF-S 18-200mm f3.5-5.6 IS which is not a fast lens, meaning when I'm zooming in on the action, my minimum aperture is 5.6, so although IS doesn't stop action (raise your shutter speed), it does basically eliminates camera shake which is the main cause of blurry pics. Now your looking at the 70-200 f2.8 which I have used on several occations (Non IS version) and it is a great lens. Shooting at 2.8 really helps low light shooting... big time. You can usually get a fast enough shutter speed in low light that you wouldn't need IS. IMO the only time you would "need" IS on the 70-200 f2.8 is if you were stoping up and shooting at f4.0, f5.6, or higher in low light. If your shootingmostly day games or use a tri/monopod, you definitly don't need it. I'm in the same position you are. I am planning on buying one of these lenses(70-200 f2.8 IS or non IS)in the near future and I'm undecided myself. I was dead set on getting the IS version until I shot with the non IS. If you've never shot at f2.8, you'll be amazed what it can do. Maybe rent the IS version and try it in low light situations with and without the IS on.


Hope this helps,


Steve