As for the radio vs. infrared, good catch…I was noticing the limited range outside and had thought “too bad it’s not RF”, and for some reason that stuck in my head when writing the post. I’ll make an update later tonight.

Second, interesting thoughts on the battery. I own an ST-E2 and have the non-rechargable lithium version of the 2CR5. I doubt it comes in a rechargable NIMH, simply due to demand (there isn’t as much for these as say, AAs). I suppose I could be wrong there, though.

In my opinion, it’s a moot point. The lithium works plenty well. The ST-E2 doesn’t require much juice and the battery lasts a LONG time in it – for thousands and thousands of shots. I’ve had mine for 6+ months and haven’t changed it yet. I’d say you could have a primary in the unit, one backup battery in your bag and probably call it good. That would help avoid the recharging issue altogether.

Also, as a small note to your original post, the ST-E2 isn’t radio-based, it is infrared. Radio transmitters, like PocketWizards allow much further distances and don’t require line of sight. The ST-E2, though, has a somewhat limited range (especially outdoors) and needs either a line of sight, or a room where the infrared pulses can bounce around and make their way to the flash. That being said, I LOVE my unit – it works very well.