Does sitting = death?
scienceblogs.com
scienceblogs.com
Best is to sit, but NOT CONTINUOUSLY. Approximately every 30 minutes, you need to get up and move around for a couple of minutes. Details here: http://ergo.human.cornell.edu/CUESitStand.html
http://iphonedevelopment.blogspot.com/2011/12/brilliantly-si...
I've found that a hospital overbed table ($50 on amazon, make sure you pick one that goes 28" to 50" or so) is a cheap way to evaluate -- I've been using it daily for over a year, and I feel no need to upgrade to a full desk -- but I also know that if I do want to switch, $500 for a full desk is worth it for me.
Both my back and my feet feel pretty good.