I just moved into a new house and there is a Trane TAYSTAT241 thermostat installed. I have attached a picture of how it is currently wired. I want to replace this thermostat with a programmable thermostat, but I'm not sure which one would be a good replacement. Also, I have no experience with thermostat wiring, and it seems like it can get tricky hooking it up to a new thermostat with different wire labels.

Are there any suggestions for a good programmable thermostat that will be an easy swap with this one? Judging from the wiring (and since I'm in Oklahoma), it appears I have a two-stage heating system.

Any help would be appreciated.