When I went to Santa Fe, I didn't care for the city itself but I loved going to Tent Rocks which is between Santa Fe and Albuquerque.
http://www.explorenm.com/hikes/TentRocks/
I also really liked doing the tram in Albuquerque and there are a lot of nice walks once you are at the top of the tram.
If you are just going to be in Santa Fe itself, I think you could easily see most things in a day. Also, when we went, we were told that they open up certain museums for free on Friday nights and we walked through the one museum that is in the presidential palace as well as another one. If you like church architecture, the basilica is interesting.
Also, we found that Santa Fe is an early city for the most part so a lot of stuff closes early and actually Albuquerque was mostly the same way.