It's not clear from the original post if he is asking about TX or RX batteries.

I'm using the packs PKH listed on JR, Hitec and Polk transmitters without any problems what-so-ever.
I do charge the LiPo's via an external charger though.

For receiver batteries, I also use LiPos as they are lighter than equivalent NiMH or NiCD's.

However I always use a BEC on my planes when I'm powering the electronics with LiPo's.

JR sells BEC and regulators, but I've been using Turnigy 8A output regulators on my medium planes and up.

On smaller planes I use the same smaller 5A BECs often used in electrics.