As a point of comparison, here's the arithmetic on LX3 batteries:
The LX3 batteries are 25-26 grams each and aftermarket batteries are about US$9-10 each. If I carry three, for about 75g I can conservatively count on 1000 frames, more if I don't frequently use the flash or review my shots.
One pair of NiMH AA cells is about 60g while two disposable Li AA cells about 30g. (Alkaline cells are for emergency backup only because they yield perhaps a tenth as many frames.)
For typical unsupported backpack trips ranging from a night to a week, there's no longer a compelling reason to fret over camera battery swaps or recharging in the field. It's both weight-efficient and frugal to carry one or two spare Li-ion cells.
For extended trips, especially overseas, it gets more complicated. IF you have an AA camera and IF you can buy lithium AA cells, you're fine. OTOH it may make more sense to use a camera that takes OEM cells (most of them nowadays) and pack your charger. Most chargers are quite small and work internationally, e.g., My (US-spec) LX3 charger is 57g.
Going back to AAs, if you have a lot of additional AA gear (flashlight, GPS, radio, etc.) then an AA camera along with a bunch of NiMH cells and a light charger looks more attractive. But as noted in the thread the selection is becoming limited.