Be careful, as a lot of the ratings are garbage.
I have been using NIMH, NICD, for over 10 years, used in everything I own that takes batteries.
The charger is MORE important than the batteries as a bad one will kill them in no time.
Don't even waste money on NICD, or NICKEL CADMIUM/nicads in normal speak as they suffer from memory effect, in that with every use they get weaker and hold less charge, even when doing complete discharges before every charge, complete waste of money these days.
Get NIMH, or NICKEL METAL HYDRIDE, these will have a capacity of between about 1300mah, to 2700mah.
For the money UNIROSS certainly take a lot of beating, from Maplin's etc, these NIMH do not suffer memory effect, and still give out full voltage up to 80% discharged, whereas it goes down a lot on NICD.
If you want performance I have yet to find better than ANSMANN, the batteries are a bit pricey, as are the chargers but ace.
Energizer and Duracell are crap IMO.
I currently use/have over 100 AA rechargeables, plus AAA, CR123 etc.
My ansmann batteries(4XAA) when in my Fuji Finepix 9600S digi camera take in excess of 800 pictures at 10 MEG on one charge, so you won't run out.
tabetha