+1 to nscrbug - rims, hubs, spoke count and type. It's largely about weight, and preferably weight on the hub rather than rotating weight on the rim, but you want a nice balanced package for whatever you want the wheels to do. Manufacturer's websites and the likes of Wiggle/Chain Reaction can give you a guide to the pricepoints. If you trust your LBS man, maybe ask him for some recommendations as a shortlist you can research.