I agree - given the choice of the SB400 or the SB700, I choose both! I only have the SB400 right now, and I wouldn't give it up for the convenience that it's size provides. I can bring my D7000 with my 35mm f/1.8 and my SB-400 with me to casual events and it's perfect. The SB-700 would be too big for this. However, I find myself wanting to experiment with off-camera flash and all the stuff that goes with that. The SB-700 is perfect for that, whereas the SB-400 is almost useless for that (aside from using certain expensive radio triggers). I have also encountered rooms that were too big for the SB-400 to bounce (20+ foot ceilings) and times when I wished I could aim the flash sideways.
I agonized over the same decision when I bought my SB-400, but i think that the right answer is both. I could settle for either one, but they serve slightly different purposes.
I agonized over the same decision when I bought my SB-400, but i think that the right answer is both. I could settle for either one, but they serve slightly different purposes.