Came across this sometime back ... this is a video of Roger Cicala from http://www.lensrentals.com where he compares a bunch of the big guns from Nikon.
On display are (in order) ... Nikkor 80-400mm AF VR f/4.5-5.6D ED, Nikkor AF-S 300mm f/4D IF-ED, Sigma 50-500mm f/4-6.3 EX DG HSM (the Bigma!), Nikkor AF-S 300mm f/2.8G ED VR II, Sigma 120-300mm f/2.8 EX DG HSM, Nikkor AF-S 200-400mm f/4G ED VR II, Nikkor AF-S 500mm f/4G ED VR and Nikkor AF-S 400mm f/2.8G ED VR.
If you get over the visual fest, then you can head to some of these sites for some reviews and views based on actual usage ...
@ ByThom ... http://www.bythom.com/nikkor-telephoto.htm
@ Natural Art Images ... http://www.naturalart.ca/artist/fieldtests/4waysto400.html
While I dream about some of these lenses all the time, a video like this puts things in perspective ... though it won't stop me from thinking about the 300 f2.8 or the 500 f4 ... hmmm! Nor will it stop me from enjoying such lewd videos ... :)
Also, remember that the Nikon 1 V1 with the FT1 adapter and the Nikon 70-300 VR gets you a light, compact and cheap (though slow) 189mm - 810mm zoom lens with vibration reduction, that you can almost run a race with ... the whole package is smaller than the smallest lens in this video ...