Kona
Surly
Brooks (maybe just a set of saddles for folks to try, and you order the one they want)

TOOLS! Several varieties of tire lever (like the Crank Bros Speedlever) and shapes of Allen wrench (Ts, Ls, foldy-things) Leathermen, pedal wrenches. Pressure gauges. The sorts of thing the average Joe can be told to use or would cheerfully buy so they'll have a spare.

Cold pop. My LBS has a fridge full of canned pop for $1. I'm always surprised by how many cans of pop they sell while I'm there.

Good bike parking.

Clean bathroom.

Classes at the shop.

Rides starting from the shop.

Socks with your logo and shop name on the cuff.