ORIGINAL: mike109
Lately I have been using Sanyo Eneloop NiMh batteries when I can get them. They have a very low loss rate in storage and do not loose charge over many weeks though I usually top them up before use and cycle them every couple of months. They really are worth the little extra they cost.
Ansmann Max-E cells are probably even better than Eneloops (I've been working with them professionally), if you can find them with tags. The only thing I'd say about Low Self-Discharge (LSD) NiMH cells is that they don't like high currents. However, R/C duty cycles probably won't trouble them unduly.