If you're using non-rechargeable (primary) batteries,
this site lists comprehensive testing on most brands available.It's well worth spending a few minutes to look through the results. The bottom line is that the cheap alkaline batteries are just as good as the more expensive branded ones such as Duracell or Energizer. Kodak Xtralife from pound shops or Ikea batteries are the best of the bunch.
In the long run, rechargeable batteries are cheaper. In fact, for high powered lights such as the Hope 1, rechargeable cells are the only way you'll get anything approaching reasonable performance. I'd suggest that you avoid the high capacity nickel metal hydride batteries. To get the extra capacity, they cut down on essential components such as separators. The upshot of that is a more fragile battery with a shorter lifespan and high self discharge (it goes flat quickly by itself without use after you charge it). By all means use them if you absolutely need the extra run time, just don't expect them to last more than a year or so at best. I'd recommend you use low self discharge batteries such as Sanyo Eneloops or Uniross Hybrios. They have a little lower capacity, but they hold their charge for well over a year, work better at low temperatures and are much more robust. I've used them for six years now, and I like them. The best thing is the reliability: they just work. No unexpected flat batteries when you come to use your light and I haven't had a single cell go bad either.
