Interesting question - and having gone through the upgrade process moving from a D80 to a D600 I agree that it does come down to how you feel with your gear (and your budget). I was really reluctant to move to the D600 but had hit the wall with the D80 after almost 5 years of good solid non-pro use (close to 23000 actuations). I've taken lots of good shots with the D80 but was finding that in low light it was limited (400 ISO+ seemed about the max).
D800 - too expensive and file sizes too large for my needs, D600 - QC problems and the build quality were initial turn offs for me ... was hoping for D300/D700 style build, D700 - couldn't find one in my neck of the woods and any that were available were only a couple of hundred less than the D600.
Anyhow, did end up going with the D600 when it was on sale over Christmas - figured that was the best price for the camera + kit lens and that it would be a bit of wait before it hit that price point again. I've gone though the oil and dust issue and ended up sending the body off to Nikon for servicing (shutter replaced, 7 days without camera). Already had some good FX glass so no need to upgrade the lenses as well.
When all is said and done though, I feel that I've definitely made the right choice - I've grown to really enjoy using the D600 and the dynamic range is stunning. When I had to go back to the D80 while the D600 was being serviced it was like having coffee with an ex. Bottom line, if you're not enjoying using your camera it's likely that you won't use it very much.
A new camera can inspire new creativity though. That's why I'm really looking forward to when my Fuji X100s arrives - different style of camera, different style of shooting! Maybe you're considering new gear as a way to push your creativity?
Good luck with your decision!
>Hi all, >This is my first post. > >I got a D200. Had few nikon camereas for during past few >years, have used D100, D300, D70, D50, D40, D40x and D80 >during last two-three years (all bought 2nd hand) just to get >a feel for digital photography. Finally ended up with D200 >(Yes downgraded from D300 since I was satisfied with d200 (of >course d300 was better, but for me it seems D200 more than >good enough to begin with or ended up with)). So have been >using D200 for about six months now. I have not really >mastered it fully. I am thinking of keeping it for some while >till I get this right. I feel like each time I upgrade more >time is wasted on mastering the camera than improving the >techniques of photography. So I have decided to use it even if >its limitations such as higher iso noise and low battery life. >However I am not sure this is the right decision. What do you >guys/gals think? what about focusing and other stuff that I am >going to miss. > >Regards