Long story short, I got a good deal on a D80 body only, jumped on it. I was using a SB-400 speedlight with my D40x and its great, but I heard that the D80 works better with SB-600 or 800. I do like to use the SB-400 for indoor photography a lot, but I wonder what would I benefit from, lets say, the SB-600? Does the flash offer anything for outdoor shots? I'm thinking about doing portraiture shots with my friends and family (might pick up a 50mm 1.8 or 1.4 soon). In short, using a D80, what would a person gain by using an SB-600 over the SB-400?