In years to come many of use could have our own little musuems of old Nikon DSLR's !
I still have my Coolpix 5000 & a D70, not worth selling but the D70 is still a great camera.
As for my D300, this is my camera for the next 4 years at least. I am still getting to grips with it & it has all the features I could possibly need in the forseeable future and has many I will never use.
Plus I want to replace my 18 to 200 Nikon VR lense with something sharper.
As for the Dx versus Fx debate, this I believe only effects those who grew up using 35mm film camera's and are familiar with the format. I never got on using film & to me the Dx format is the norm so until I am convinced that there are benefits to my photography using FX then I will stay in the Dx camp.