I wouldn't really consider an RC transmitter a high-draining device.

I would suggest a newer type of NiMH known as low static discharge (LSD). Unlike older NiMH which would lose their charge if you left them sitting for awhile, LSD NiMH can be charged and they will stay charged at close to full capacity for extended periods of time

I use Turnigy LSD AA NiMH in my transmitters and they have worked out well. Sanyo Eneloops are also popular. There are plenty of other brands too, just search for LSD NiMH.