I am installing a honeywell prog. Thermostat model rth7000. All of the terminals match the old one with the exception... old one has white wire going to terminal x, the new one does not have a x terminal. Where do I put the white wire on the new one?. tanks!

Go here for your diagram.

http://customer.honeywell.com/techlit/pdf/69-0000s/69-1900EF.pdf

Usually the white wire goes to W1