theres some really good write ups with pictures on how to turn a wine cooler or refrigerator into an incubator in the DIY section of the forms, im building one right now out of a 32 bottle wine cooler and i bought a herpstat 1 basic for $115 bucks and $10 shipping to run it on and it has built in fail safes so you don't really need a back up tstat altho im sure it never hurts to have one =P
From my research i would have either gone with the herpstat basic for $99 the herpstat 1 basic for $115 or the herpstat 1 for $140... i believe any of the three would be fine read the features see what ones best for you would be my advice, but from what i understand with the recent advances for the money herpstats the way to go