Summary: The SB-600 is available for cheap used. It works great, once you set it up. It takes a bit of programing with an arcane menu system to get it set up... To see a more thourough review and example glamour pic taken using the SB 600, see http://glamourphotography.co/?p=4609 For 90% of users, perhaps the best choice in a speedlight.
Pros: Lowest priced speedlight compatible with Nikon Creative Lighting System
Nikon SB-600 Speedlight review by libertinephotography
16 September 2008
Summary: The SB-600 is a wonderful mid-tier lens (if you notice, the cons that I stated are largely resolved in the SB-800, but for a LOT more money). What I really love about this flash is that it is CLS functional even as a wireless slave. This feature alone is worth buying, so long as you have a commander unit. A nice "strobist" kit for almost any situation with a CLS-compatible camera is the R1C1 and two SB-600's.
Pros: Useful Programming, Can Be Used As A Wireless Slave, Good Guide Number
Cons: Recycling Time, Cannot Be Used As A Commander, Limited Customization of Features
Summary: You can take spectacular photos of any social gathering with the panning and tilting head of this flash. Getting an external flash is not primarily about having more power or being able to take more shots continuously (unless you're a paparazzo), but about being able to control light.
Pros: Pan and tilt head transforms photos of social events, recycle rate useful for action shots
Cons: Bouncing can be tricky, widest f-stop must be forced on D80
Summary: This flash has done as much to improve my photography as any of my lenses. I guess that's the best compliment I can give a piece of camera equipment. I use it with the Tamron 17-50 and 90mm on a D80. Generally, I keep the lenses wide, and turn up the ISO so the flash isn't doing a lot of work, just slightly supplementing the available light. The results are amazing.
Pros: fantastic pictures, simple, flash meetering is fantastic
Cons: AA battery management, Only twists past 90 degrees in one direction?
Summary: I hesitated quite a while before I decided to go ahead and buy this flash. Haven't had any regrets. I've looked at Metz's iTTL flashes but am glad I got me a nikon instead. This flash integrates so incredibly with my D50! Using it is very simple, power down the camera, slide it in the hotshoe, lock it and power up both devices. Slap on an omnibounce and tilt 60 degrees up and you'll get decent images every single time. Got a white ceiling?
Pros: All the power I need in a very simple package
Summary: Having used this flash unit at work, I appreciate the additional illumination it offers over that built in to the Nikon D50. However, the main benefits of using this flash unit is the ability to bounce the light off the ceiling and to diffuse the light. This leads to softer lighting of portraits and far less red-eye. The downside is that it requires a specific battery whereas the newer SB-400 can run on AA's and thus can more easily use rechargeable batteries!