I'm going cheap lol, What I really want is more reach. The logic then would be to go for the highest zoom like a tamron 150-600. People say it is not very sharp, but many people say its good, flickr pictures of many songbirds look good, and the difference is probably small. I can find a used tamron for around $700 or less. A 7D is about the same as a t3i in image quality, you would be getting a better autofocus system and more frames per second, not a big deal. I could spend tons of money for little benefit in image quality, not worth it. I guess this is the best bang for buck.