If you have the equipment to charge NiMh I would suggest this Pack from www.all-battery.com

http://www.all-battery.com/6v2000mah...ctor11106.aspx -For $7.99

I have a good luck with them and I like the added power and speed of 6V packs. If you want to stick with NiCd I would look at the their Nicad stuff as well. The prices are cheap and the packs are good quality. I am not a big fan of the over priced OEM packs that have 6-700mah and may get 3-4 flights before requiring a recharge. I average 5-6 flights on my 6V 2000 mah Nimh packs. I load test my packs after every day of flying and still get, at most, a .5 voltage drop.

I would also suggest looking into purchasing a decent battery charger that has the ability to cycle NiCad and Nimh packs. This is the one I have for my Rx packs.

http://cgi.ebay.com/Hobbico-Pro-Seri...item3364a62667
I got mine used like this one. Works like a champ!