I use the 580EX II speedlite. There are CP-E4 external battery packs available for it (and most canon flashes, the battery packs take AA's as well, just more of them so you don't have to change them as often). I just burn through AA's and keep changing them because I dont need a wire coming out of my flash to get in the way. It actually ejects the batteries with quite a bit of force (which is good because when shooting constantly they are too hot to touch) and then I just throw 4 more in.

At any rate, canon doesn't make a rechargeable battery pack for any of its flashes. And using rechargeable AA's doesn't work very well. They don't provide enough power and have to be changed much more often, and they die very quickly because being abused like that really shortens their lifecycles. In fact I think there is a danger that certain types of rechargeable AA batteries might explode under such abuse.

Mine does stroboscopic, you're limited in your power output depending on how many strobes and how quickly they fire. I'm not sure but I think the 430ex probably does strobe as well. Its called "multi" in the flash's menu.

The focusing assist is awesome. The built in focus assist on my rebel XTi is so useless I actually disabled it because all it does is distract people and animals, not focus the camera. The focus assist on the 580EXII will focus perfectly on a FLAT WHITE WALL from 20 feet away (canon claims 30ft but I haven't tried it) in a totally pitch black room. Thats something regular autofocus cant even do in daylight usually, and the flash WILL fire up the focus assist in daylight if the scene has too little contrast to get an autofocus lock. Some cameras can disable the flash, I dont know if this will turn off its AF assist beam or not (it probably will). There is a trick you can do though. Set the 580ex to master, then set it not to fire its own flash. It still fires a preflash (so it knows the exposure to send the non-existant slave), but it SHOULD happen before the exposure happens. Although I've never tried it without an actual slave attached, I just tested it and it appears to work. I always just use bounce flash or the ST-E2.

Another option for assisted focus on the canon is the ST-E2 speedlite transmitter. Its not a flash, but it attaches to the hotshoe and sends ETTL-II signals back and forth between remote speedlites via infrared light. Its great to get your flash off camera (light coming from the camera is flat, unflattering and abnormal looking) and if you don't own a flash, it'll still give you great focus assistance. Its also much lighter than a flash (its the size of a pack of cigarettes) and its expensive, but still cheaper than even the 480ex. If you only want auto-focus assist, this is the way to go.

As for burning man, there is dust in the air even on the clearest night that you cant see with the naked eye. Fire off a flash anywhere near your camera and you're going to have white specks of dust out of focus (huge and blurry) all over the image. Its the dust about 2 feet in front of your lens and it will drive you completely insane. You really need to get the flash off-camera or even better invest in a battery powered studio strobe kit like the Hensel Porty for an arm and a leg or buy a cheap (as cheap as a flash) used studio strobe and just run a long extension cord to your friendly neighbor's generator.

Then again, this post is old, so you may have already experienced that evil dust reflection. :)

There are two external battery packs one could use depending on your budget and which strobe you wish to obtain.

If you wish to use the Canon 580EX II, you must get the more costlier Quantum Turbo pack and Cord combination, which plugs in their High Voltage socket, the Canon branded external battery, I've used from a friend sucks, the recycle is too slow.

I've used Canon 550 EX with Quantum Battery one plus pack at Burning man which is less expensive than the turbo, however this is not a high voltage pack.

The cord which is designated for the Quantum Battery one plus for the 580 EX II will not allow the door on the battery compartment to close which will compromise the air sealing capabilities of the unit.

I read somewhere that Lymedyne battery packs could be used for Canon 589 EXII as external high Voltage battery packs, but I have not personally experienced this.

At Burningman I have used Hensel 1200 Porty b about $1900-$2200 and Profoto 7B2 about $4000 new. If you have cash, I would go with Lymedyne kit or Profoto 600 b battery powered pack.

My setup at Burningman was using Pocketwizards in both the Profoto and Hensel setups and an Avenger rolling movie stand. Multiple flashes can be achieve with an assistant hitting the button several times, with the shutter opened.

check out my pics:

public.fotki.com/abjectpho...re-perfor/

Kyle, check out the Strobist site, at strobist.blogspot.com/
They have some great reading on specifics of off camera strobes.