Basketball: 70-200 is king. A shorter lens would also help, say a 24-70 or some such.
Football: American football or soccer? I've used my 70-200 for good with nice results, but both demand more lenght. However, both are played outside, often at night. If they are at night, just used the 70-200 as best you can or underexpose an f4 300 (wouldn't recomend). If they are day time the 300 f/4 or the 400 f/5.6 would both be great.
Recitals and plays: The 70-200 will be excellent, but also think of checking out the canon 50 1.8 (or 1.4 if you have the cash). The focal length is nice for stage, and the fast aperature will be amazing.
Hope that helps a little, let me know if I can do anything else.
-macgyver