I use the EF 300mm f/4.0 L USM (no IS) for a lot of daylight sports and I think it is a great choice. It is certainly lighter and less expensive than the two big f/2.8 primes and it is a tad sharper than the 70-200. If you do choose the EF70-200mm f/2.8, you'll have an outstanding and versatile lens.


I rarely see the EF400 f/5.6 and I think it is just a tad too slow for anything but brite day shooting.


You can't go wrong with the 300.