So, I bought a S3 a while back to see if I liked photography, and became hooked. I'm looking to upgrade to a dSLR. I'm trying to decide what set up to get, im almost set on a used 20d (for the faster fps, solid build quality, and better high iso performance), also a 50 1.8 for obvious reasons. Im trying to decide on a good lens for out on the track. I figured this would be the place just because so many people on this forum has so much talent in this area. Does a 70-200L sound about right? Im leaning to getting the 2.8 but might settle with the 4. I do have a budget to stick to, but don't mind investing in good quality glass. Any input would be great on these two or any other lens to start out with.