I found a possible bike this evening: a Trek 7.3 FX hybrid. Originally $619.99, it is on sale for $439.99. I would probably have bought it tonight if there had been time to test it out before the shop closed. As it is, I will have some time to research it before I go give it a test ride on Thursday (mandatory orientations are happening for me tomorrow and Wednesday, on the opposite side of town).
The bike has Shimano Deore components, which the salesman tells me are the 6th of eight levels of quality sold on hybrids. It is quite light and seems well constructed. The place promises free repairs and tune-ups for a year, as well as an unspecified discount on a helmet, lock, and pump.
This is the last one available with a 20″ frame, which I am told would suit me better than the 22″. Hopefully, nobody will snap it up before me.