Really, at RS? I'd have believed rechargeable lithium AA cells - CR123s seem a little obscure for them, but maybe so.
Things to consider:
1. Some are 3.0V, some are 3.6V - depends what you want.
2. Some are "protected", meaning they shut off before getting discharged past the point of doing themselves damage. Some are not.
3. At DX, if you can stand the wait, it's gonna cost you like 1/3 of RS.