Uniross Hybrio batteries are excellent; I am so pleased with them that I am phasing out all other brands and now have sixteen of the 2100mAh AA-sized hybrios and eight of these 800mAh AAA-sized. These are all mainly used for high demand photographic applications and they have not let me down once.
Hybrios use Ni-MH cells which are quick to charge and quick to power-cycle (which makes them ideal for modern flashguns).
The hybrid technology means that they do not discharge quickly when not in use, and some tests show that with a full charge they can still have more than 75% of their power left after twelve months on a shelf!
I strongly recommend moving to these batteries in favour of alkaline or inferior rechargeables - they are not just worth it in economic terms, but they sport great performance when you need it most.
Don't forget to recycle your old batteries when they're dead! I put mine in the special bin at Asda ;)