LumiQuest ProMax Ultrasoft Bounce Flash Device

Bought this item from a local camera shop... boy was I supprised, used to use the stofen plastic bouce box, man what-a-difference. This thing works great, it raises the flash so high, and softens it just right, really gives your shots that nice soft look. Also, keep in mind that this cuts upto 2 stops of flash power, so as with all diffusers, bring either a extra set of bateries, or invest in a turbo battery(400 bucks, but makes recycle time nonexistant).
Buy LumiQuest ProMax Ultrasoft Bounce Flash Device!

Sigma EF-530 DG Super Electronic Flash for Nikon DSLR

Do yourself a favor...spend the extra $50 and get the Nikon SB-800 instead. I initially bought the Sigma EF-530 DG Super as a lower-cost alternative to the Nikon SB-800, and I regret it. I ended up buying the Nikon SB-800 after all.

Any way I use this flash, either standalone on-camera, wireless master or wireless slave, I have to make manual adjustments to exposure because it always over exposes. In addition, as a wireless master, it often miscommunicates with the slaves, resulting in slaves firing at full power, not only over-exposing the subject, but also wasting battery life.

To setup as a wireless slave, you must first attach the flash to camera, make your settings, then remove it from the camera. Then if you turn off the flash or accidentally press the "mode" button, you have to re-attach it to the camera and make all you settings all over again. Such a hassle. In comparison, the Nikon SB-800 or SB-600 can be setup as a wireless slave without having to attach the flash to the camera, and when you turn the Nikon flashes off and back on again, all the settings are the same a you left them, so they're always ready to go straight out of the bag.

One more thing, the menus on the Sigma are very cumbersome and not very intuitive.

Bottom line, if you're only ever going to use this flash as a standalone, and having to play with exposure settings is worth saving $50 to you, then you might be okay with the Sigma EF-530 DG Super, otherwise go with the Nikon SB-800.
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Sigma EF-500 DG ST NA-iTTL II Flash for Nikon Digital

On a D70 it feels well balanced.

Powerful flash -- guide number of 50 @ ISO100 and 105mm makes this a very powerful light. In TTL mode it could keep firing while I shoot continuously @ 3fps (!).

Good exposure -- This flash gives me excellent, consistent exposures on a D70 in Matrix Metering: both the camera metering system and the flash quality contribute to exposure predictability. Suggest everyone to check reviews of this flash with the specific camera.

Great value -- although this flash lacks wireless, which makes this somewhat "on-camera-only", it gets you pretty far into flash techniques, without superfluous features.
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Canon CP-E4 - Flash power pack

I'm a wedding photographer by profession. I put off buying this because it was so expensive and I was doing just fine carrying extra batteries and changing them when I noticed they were running low. I purchased it the other day because I was getting sick of missing 1 or 2 out of 5 pictures in quick-sequence shots (bouquet-tossing, cake cutting, etc).

After just one shoot, I have completely fallen in love with it. I was able to fire off sequences without missing anything, it recycles my flash supremely quickly and I only wish I'd bought it sooner. I will actually be getting rid of my 430ex backup flash so that I have two flashes that are compatible with this.
Buy Canon CP-E4 - Flash power pack!