If you are looking for athletic shoes or just something retro/classic (like these great soccer-inspired Lunza Contender sneakers) you should check out the latest from Reebok. Their store sells shoes and apparel for men, women, and children. They also offer official pro-league merchandise such as MLB logo shoes (you have to get your green shamrock Boston Red Sox sneakers) and everything NHL (Reebok is the official outfitter of the NHL).
Before you jump into this store, make sure to click through this offer for $10 off orders of $75 or more throughout the store. As always make sure you read all the terms and conditions.