I would have to agree, based on the pixel density being different. So even if the area is the same, you wind up with more pixels with a D300. Since I have not used a FX camera before, I just did not realize you could force a FX lens into crop mode.
You could always crop in post processing, but in sports that could mean over a 1000 frames on Saturday, so I would rather not go that route. My needs aren't compelling for FX, but after this season, I will sell my D200, keep the D300 and see what new equipment will be available in June 2009. If that becomes a D400 or D700 I think I could be happy either way, it really just depends on the price.