I was looking for a moderately priced zoom lens with long reach for sports, and I chose the Sigma 120-400mm f/4.5-5.6 AF APO DG OS HSM Telephoto Zoom Lens for Nikon Digital SLR Cameras.
Below are a few example shots, and here is the full gallery on Picasa.
My outfit with the new lens.
It's a bit heavier and slightly longer than the Nikon 80-400mm.
The shots below were taken from my deck, with the lens fresh out of the packaging, and are the first things I shot. I was far toe excited to mess with the controls, so I was set for ISO 500, continuous focus, left over from the last ballgame I shot. They're freehand, and I can already see that the OS works well.
400mm, 1/125s, f/5.6, ISO500