For outdoor sports with big fields (soccer) you may want to consider the Canon EF 100-400mm f/4.5-5.6L. It's range is unbeatable. Like many other posters said, I would consider a fast prime as well you back up your 70-200 f/2.8 for indoor sports. You can pick up the 50 /1.4 for about $350. It's L counterpart is well over $1,000.