I'd recommend the 70-300mm L - which is sharper (especially at the tele end), better AF, more contrast and superior IS and a bit 'faster' than the nonL lens at the same focal lengths.
On a crop body (eg T2i or 7D, etc) - it's effectively a 480mm, which- when having decent amount of MP (18MP) still allows a decent crop.
I find 70-200mm short for such outdoor sports, though of course the constant f/2.8 is handy for stopping action.
Otherwise going for a large prime (eg 300mm f/2.8 or 400mm f/2.
is going to cost you a lot more money. I love my 70-300mm L for outdoor work... both occasional sports - and great as a walk around wildlife lens too.