The custom saber shop is a great place for making and designing your own saber.
www.thecustomsabershop.com

If you own a master replicas and wanted it upgraded or you are addicted to the movies then ultra saber has the sounds and light up effect.
www.Ultrasabers.com

If you plan on dueling with your saber then park saber is where you should look.
www.parksabers.com Or www.buystarwarsstuff.com (both links are park sabers)

P.S. I got mine at Buy starwars stuff and I love it.
May the Force(Tao) Be with you,
Master Jedi