So, what's next, you say? My verdict - Full frame territory. Or just wait for the Nikon D400 to break the current DX mould. It's just not worth the effort to start the engine on the Nikon D300 series...it's too old school, too dated, in my opinion. Too predictable.
Well, I am almost set to go the Nikon D3000 road instead of the full frame road for a simple reason. I don't need killer low-light performance. I have both my Nikon SB-900/SB-400 speedlight to guide me through that death valley...I am cool. Besides, the 1.5x crop factor is beginning to show her tail of advantage, when I need just that extra reach. However, for those pro readers out there, yes, it may well be the only road for you.
The DX land is my home now, or until we see a new format on the Nikon horizon. From the consumer point of view, its still anybody's game concurrently. Nikon is good. Nikon D90 is better. Wisdom to appropriate knowledge is best.
Perhaps, the Nikon D700x will change all this all over again...let's all wait for Fall 2009.