well, this is not that easy if you invested in glass already.
Yes it is.
Buy something that fits your lenses but is better than what you have.
If there's nothing better or nothing you want to upgrade to then why does it matter? Just keep using whats already working for you.
Not directed at above, but in general...
A helluva lot of these whiney posts about what Nikon are doing seems more about brinkmanship or bragging rights or keeping ahead of the Joneses than actually about taking pictures or shooting video.
I don't need 36MP. If I did I'd already have a 36MP camera. I can deduce therefore that the D800 doesn't matter to me.
Not much that Nikon is up to does matter to me.
I don't use them. I use canon. Quite happily. Selfishly speaking from a video perspective I think the advances on the 5D3 are great. Headphone socket. Breaks the 4GB clip limitation. Choice of temporal and spatial compressions. All very useful and very welcome upgrades. That it also gets a 1D style AF system is brilliant for my stills. I think the 5D3 is great. A very logical and considered upgrade.
I might even buy one. But then I never had a 5D2 (although used plenty)
If I was sitting here with a 5D2 would I be annoyed that the 5D3 didn't represent a great value upgrade? Nope.
I'd keep using the 5D2 and await the 5D4.
Nikon didn't enter into it once.