The 300mm f/2.8 VR is one of Nikon's best lenses. It's not too heavy, and the Vibration Reduction system delivers 3 stops of anti-shake compensation, so it's very popular with sports photographers. It can be used hand-held, but a tripod or monopod is recommended.
This lens works very well with Nikon Teleconverters and it will still deliver superb image quality. The 1.4x Teleconverter makes it a 420mm f/4 lens; the 1.7x Teleconverter makes it a 510mm f/5-ish lens; and the 2x Teleconverter makes it a 600mm f/5.6 lens. All of these combinations will retain autofocus and VR on all compatible cameras.