I have had very good results with my Brewers Edge (http://www.williamsbrewing.com/BREWER_S_EDGE_SPACE_HEATER_P518C100.cfm
) space heater in my fermentation chamber. If you're looking to reduce cost, the ReptiTherm would probably work well for less money, but I've never used one.
The FermWrap scares me a little because I would assume that it heats to a very high temperature in order to change the temp of the whole system quickly. That is, it may always heat to ~90 degrees and then shut off when the ambient temperature of the fermentation chamber reaches the programed temp on the controller. I wouldn't want something heating to ~90 degrees (i don't actually know how hot it could get) against my beer.
I have used ceramic space heaters before, but my temp controller does not register temp changes quickly enough to shut the heater down at the programmed temp. With a ceramic space heater plugged into my Controller II (http://www.williamsbrewing.com/CONTROLLER_II_P183C100.cfm
) I have measured temperatures as high as 90 degrees F when my controller only read 60. I think that in a relatively small space, these heaters work too efficiently.
I say go with the heating pad stuck to the side of your chamber. Let us know how the Reptitherm works out if you go that route.