It sounds like you have the right setup going. Sora isn't race quality, but they are still solid components. Wheels built with 36 spokes should be solid. In addition, Mavic builds a pretty solid rim. Just cross your fingers and hope that the wheels are built correctly. I once bought a new front wheel for cheap and the entire rim was trued about 1 cm off center.

As far as the tires, I'd take threadend's advice and do a review on them. Some tires are crappy while others are good. As long as you have enough frame, fork, and brake clearance, 700x28 is great for a commuter-style bike. Me? I now have 700x25 Michelin Axial Pros, but once they wear out, I am going to try 700x27 tires from Rivendell.