I went with the sports that are offered within our community and that in which they have met the age requirement.  My older boys play basketball, soccer, baseball and they swim.  This is the first year that they are eligible for football, but I said no.  IMO seven is way to young for football.  They would like karate, but for now it does not fit into our schedule. 

As for my little ones they are still too young for any of the organized sports.  So for now my daughter takes dance and gymnastics.