I think it is very tough to beat either the Canyon Ranch in the Berkshires or the one in Arizona if you are looking for a health oriented spa. They consistently are rated near the top in that category. They will pick you up in Albany and drive you to the spa which is in a beautiful location in the Berkshires. Ive heard the Arizona one is nice also but havent been there.

If it is a non-health related spa that you are looking for, ie with lots of good wine etc but saunas and the like, Ventana in Big Sur is excellent.