Guitar Center is a pretty cool place for musicians. You get to play with the instruments before you buy them and prices are generally pretty reasonable. The store is pretty big, so you'll find that they carry pretty much every instrument imaginable, including DJ equipment, mixing tables etc. etc.
If you're buying something over $100, they are usually willing to negotiate with you too. This is because the sales are commission based, so the employees are allowed to barter to get that sale. Always ask, because they will probably go down a little on price.
I also think it's cool how they send you coupons in the mail after a big purchase. You'll get a coupon for free drum sticks, guitar strings and other little things along those lines, but it's nice for them to recognize their loyal customers.