Nikon SB-600
Great strobe with a very solid feel. Flawless performance and great battery life that balances well on my D70s and D40x cameras. I also have an SB-800 and the two work perfectly together in Remote mode with the D70s internal flash as the master. I took a series of test shots and progressively changed the output to judge the degree of control available. The SB-600 is capable of 1/3 f-stop output control or better. I highly recommend this strobe and think it should be your first choice over the SB-800 or new (and even more expensive SB-900) unless you have the rare need to have group control over multiple flash units or if your camera's internal strobe cannot act as a remote master. Then the SB-800 is your best bet. Otherwise, save your money and use it to buy other gear.
Nikon Sb 600 Speedlight Flash For Nikon Digital Slr Cameras