Congrats, you won't regret it. I can't express how much easier it is to work with the SB-900 as a remote due to its better controls. Given, the extra second or two it takes to set the 800 and 600 isn't a deal-breaker, but you definitely notice a better flow with the 900.Thank you everyone for your guidance. I went ahead and got the SB900
He's getting a D700, so worst case he can flash the SB-900 with the new firmware (if it doesn't already have it). I personally have never run into the thermal cutoff (running old firmware), even after quite heavy use. Here's hoping you never see it.good choice.................but watch out for the thermal cutout..........!