Since no one apparently has mentioned it:

www.zen-stoves.net

The definitive authority on alcohol stove research.

I've tried multiple designs (including a modified penny stove) and found the best designs include some kind of wicking material(fiberglass/perlite). I also prefer a simple chimney burner. They seem to have the highest rate of success and with the reduced complexity last longer. When I made these for my emergency kits for my family this past winter I made a simple chimney burner following the designs from zen-stoves.net from pepsi can. It is nice in that it can convert to a sideburner if needbe. I then made a simple hobo style-wood stove out of a coffee can and packaged one inside of the other. This way there were two possible stoves and the alcohol stove got a windscreen to boot