The FX models look attractive but going FX is not an economical decision. I have all the lenses I want and they work very very well with the DX sensor. I can't see spending $2,000 for a body and then upgrading my glass... The $2,000 decision quickly becomes a $4,000 - $6,000 decision.
If the D300s wasn't so good, I'd feel bad. It only looks long in the tooth compared to the latest sensors. It was good 3+ years ago and it is still good but it is due for an upgrade.