I buy the regular aluminum case glowplugs igniters with the meter on top. The ones that can unscrew and you can pull the Sub C cell out of it. Those are basically the easiest to maintain, since I can just get a couple Sub-C rechargable batteries and swap them out when needed. Something like the one on tower site listed below.
http://www3.towerhobbies.com/cgi-bin...?&I=LXJ803&P=7