For the past seven years I have been answering this question rather than asking it, but the times they are a changin'...
Currently I have a radiant propane system which works very well and with which I am happy. However, last fall we installed an outdoor wood furnace with the capability to heat several buildings. We just heated the house last winter, but I am considering heating the shop as well. I need to make a decision soon, as we are planning on paving the driveway, and if I decide to heat with the outdoor furnace, I will need to trench across it. If it gets paved first, you can just believe I am not putting a ditch across it! What I mean specifically is, I need to decide if I am going to use this heat source at all ever. I can put the pipes in now (not a small expense) or forever hold my peace.
If I do go with heating the shop via the outdoor furnace, I have to make a choice in the type of heater that I am going to use. Probably the most economical and easiest to install would be a heat exchanger with a forced hot air system. I am not really enthusiastic about that for several reasons. Least economical (read financially unviable) is pulling all the tools out of the shop and installing a radiant heat system in the floor. I could also install some radiators in the wall somewhere, but I do not have a lot of wall space available. I am open to suggestions regarding one of these forms of heat.
I am posting to ask others what they have done that is pertinent to my sitation here. What I am looking for specifically is experience from people who have forced hot air in their shops or radiant heat via hot water in one of its numerous forms.