Strobist and thinking more about flash. A couple weeks ago I got my second SB-800, and have continued to experiment with off-camera flash.
The D70s I have will control a single channel and group (3A), and the D200 will use any channel, and groups A and B with different settings for each. Both cameras can trigger the flashes remotely via the on camera flash. It's a pretty cool technology, because it has to transmit ISO, shutter, F/stop and distance info. Also, from what I've read the remote flashes will prefire so fast you can't see it, and they will assess the amount of light hitting a subject (at the flash? at the camera?) and adjust output accordingly. I don't know if that's 100% accurate or not, but it works pretty well.
One case where I had trouble was when the flashes weren't in the line of sight of the camera. Sometimes the remote flash would fire, sometimes it wouldn't, If I were a pro, I'd consider getting the Pocket Wizards to control them flawlessly via RF (visible light).
Anyway, here are a bunch of recent shots I've taken with flash.
Green crested basilisk
Tokay Gecko (Gekko gecko)
Wattled Crane (shot w/ Snooted Flash)
Strobe on a rope - Golden-Headed Lion Tamarin
Snooted-Flash - Red-Capped Crane
And the less than perfect shot I was trying for...
Having started to use flash regularly, so much more is possible. The ability to take low light photos is just part of it. Flash, and light in general, can become a very important part of a (good) photograph.
One thing I've been burned by more than once is that the SB-800's will throw their flash at below parallel with the lens when set at 90 degrees on the flash head and on camera. This is to provide flash better to close subject. However, when you have a good telephoto lens and you're trying to light something far away, the flash's light will fall too close. When using a better beamer and 300mm or 400mm on a far bird, you won't even HIT the subject.
I noticed that with the Snoot on flash, if you jam it all the way down the flash head, it will prop up the flash head and make it work at good distances. I plan to make some snoot like shims for my flashes to correct for this low angle problem.