Our family usually goes to Big 5 when the kids need soccer or t-ball equipment. Their store carries mid-range products at decent prices. They don't usually offer anything fancy or high-end, but if all you need is a basic tennis racquet or a new basketball, Big 5 is great.
Their shoe selection is not impressive, but like the rest of the store, they carry the standards like Adidas, Reebok and Nike with a good range of kids shoes.
Their sales are very good, but you have to get there quickly or they will sell out. Check their ads in the Sunday paper and if there's something you want, go that day.