Consumer Reports tested AA cells in their 11/07 magazine. They published the results in their typical qualitative (but still useful) fashion and, since they're touchy about reproduction of their material, I'll summarize the take-home message:
1. Energizer lithium cells definitely performed better overall than alkaline, especially in high-drain devices like cameras, but also were the most expensive ($2.25/cell).
2. The alkaline cells performed essentially the same across the board, regardless of brand, so the recommendation was to buy on price. The lowest priced cells were sold by Costco/Kirkland ($0.21/cell) and performed about as well as the more costly Duracell and other big names (>$1.00/cell).
Since reading that article I mostly buy Kirkland AA & AAA, but still stock some Energizer Ultimate lithiums for situations requiring higher performance, lighter weight, low temperature performance, or long term storage. For D cells, I'm stuck using Duracell until Costco starts selling them under their Kirkland brand.
A year ago Costco was selling Energizer Ultimate AAs for a really great price (~$1.24/cell), and I made sure to pick up a couple packs each time I was there. If they start selling them again at that price I'll pick up more. In the meantime, Amazon cuts a subscription deal ($1.56/cell), so I'm buying a few per month that way for long term storage.
I also have lights that take the CR123 lithium cells. With some searching you can pick up Rayovac or Tenergy brand for about $1/cell, and they seem to work as well as the more expensive brands. I've never seen any comparison testing of these cells and would be interested if anyone has any links they could point me to.
