Depends on your needs.
The D7000 is a great camera, with lots of features, for a great price.
The D300s is a bit more feature laden, with less megapixels - but you don't really *need* them to make quality images. The sensor in the D300 and D300s is more than adequate.
It's discussed and debated to death all over the internet. Both are great products! Just depends on what you'll be doing with it!