I have the XSi with EF 70-200 f/2.8 IS USM lens... I personally love the lens and its definitely one of my favorites... my only thing is that we have a crop sensor so at times I need to change cause I'm so close with 1.6x zoom!! Oh and no matter how much you say the weight is not an issue, the first time you'll use it you are going to say **** that is one heavy lens... the upside once you switch to another lens it feels like you are carrying a P&S

On the long end... this lens is wonderful specially when shooting action.

I shot this whole AVP tournament with this lens... check out the quality... hope it helps you with your decision
2009 AVP Manhattan Beach - a set on Flickr