oh, and it might also be worth mentioning, just in case: if battery capacity and recycle speed are paramount, and if you *only* use them in your flash unit, you can get external battery packs such as the cp-e4 for *some* flashes (and equivalent in other brands) http://www.amazon.com/Canon-CP-E4-Compact-Battery-Pack/dp/B000NSJ4Q0/ref=sr_1_2?ie=UTF8&qid=1429053486&sr=8-2&keywords=cp-e4 (off-brands are cheaper)
These are hardly cost-effective for the average user, but provide unequalled performance.
