Stock the popular service autos: Glocks, Sigs, XD's, etc. Have a fair share of the classics: 1911's, S&W's, and keep a number of moderately priced options to round things out: Kel-Tecs, Ruger's, and Taurus models. Try to have a good selection in all price ranges from the $200 Kel-Tecs to the $800 Sigs and HK's. That way any customer can walk in and have a couple good guns to choose from no matter what their financial situation is. One favor though, try to consider your selection as a representation of your store and the quality you sell to the customer. Know your product and know it's expectations. Be honest. Personally I like Beretta 92's, the Sig 226, and the Glock series. Sounds like you'll be fine and I wish you the best of luck.