need advice from big lens owners....

I am saving (and saving) for faster, longer glass but am somewhat indecisive about which lens to get when I've got the moolah. I have D300, 70-200VR and TC1.7, but as those of you who like to shoot wildlife and birds know, that is great lens for many purposes, but this combo just doesn't quite have the reach one frequently wants or needs. I also shoot soccer games frequently.

I'm wondering, do you 200-400 owners find that you are usually near the 400 end or do you frequently take advantage of the fact that you own a zoom. Or, put in another way, do you think, after looking back at your longer lens usage, that I would be better served looking at 300 or 400 telephoto.
Need advice from those with experience in this area. Thanks