It depends on your budget. I like dealing with Showtime Dance Shoes (based in Atlanta, Georgia www.showtimedanceshoes.com). They carry several different really great brands. Browse the site and see what you like. Then, google the product. Sometimes you can find the same shoe a little cheaper on other sites. But, Showtime offers really great customer service.
Also, I've been impressed with Capezio's shoes recently. I bought my first pair and I really love them. My boyfriend also bought a pair and he's has been pleased with them. Their shoes are a bit less expensive, but still good quality.
There are some shoe companies that I've dealt with that offer a much cheaper price, but you get what you pay for and the shoes do not hold up nearly as well.
Good luck to you!