I just got a new lens. A Sigma 50-200mm. I like it. Compared to the Canon 55-250mm. I think it may do a better job. The next lens I may get is by Sigma too a 70-300mm. I have the Canon 75-300mm, but It does not do a great job focusing and the sigma seems to have good reviews plus the price is a good one.
What lens is your favorite?