You're sure it was a 300mm f2.8? A 4k lens isn't required to produce great pictures. There is some much more reasonably priced high quality glass. The F4L series of lenses are good and relatively cheap, and with low noise high iso abilities of the current generation of cameras make f4 very usable in almost all situtions.

Remember, with your first SLR purchase you're chosing a system, not a camera. Today I poured over the Canon leaks about their upcoming cameras, but when the same thing happens with Nikon I hardly pay any attention because it doesn't matter to me.

Matthew