Which to buy a Nikon D4 or the D800? For wildlife, its a tricky one?

No people saying 'Choose a Canon" no point all my lenses are Nikon fit. Just wanting some other people ideas and such!

Whatever leaves you budget for the lenses. As a wildlife shooter you want a long lens. Personally I'd rather shoot a D3100 with a 600mm nikon than a D4 with a simple 70-300VR.

Having said that, the D4 would be the obvious choice because of it's extreme build quality

Sorry, but since you have to ask you don't need either of those - As previously stated, an entry-level DSLR w/ good glass would be a better investment.

It depends what lenses you have.AI lenses won't autofocus and play havoc with your metering modes; cropped-sensor lenses are too short.

Unless your gadget-bag is full of AF 35mm Nikkors (in which case, you wouldn't need us to make up your mind) you'd be buying new lenses sooner or later anyway

Obviously the D4, this is the job it was designed for. The D4 has better AF, it shoots faster, and is built to rough it out in bad conditions.

Of course if the D4's £6000 asking price is a little steep, the D3/D3S is nearly as good.

I would suggest you buying Nikon D7000 along with a good zoom lens