Watermelon Music is a great store for buying (new or used) or even renting electric pianos, drums, didjeridoos, guitars, violins, violas, cellos, etc; they have a variety of other instruments. They also do musical instrument repair which I though was cool. They also have this deal where you can buy guitar strings as 2 for 1 as long as you use $2 bill.
They have a pretty good selection of sheet music in the back along with various learning tools. The salespeople are always really friendly and knowledgeable and they do let you try out most of the instruments. Music lessons are also offered through the store.