What is the most useful camera from Nikon?

I have a cheesy version of a Nikon camera, but now I want something with a bit more features to it.

It really depends. I'm personally a Canon fan, but that's just me. What kind of lens were you thinking of? If you want the best, it's gonna cost a little money…

If you mean dslr and versatility. Then that would the starter dslr d3200. Once you get more specialize like sports or landscapes. Then you narrow it down to more expensive cameras like the d4 or d800.

What camera do have today? Model number? Budget? What is most important to you to photograph?

My personal opinion is that the best, most versatile cameras available don't unfortunately come from Nikon. Probably the most flexible single camera on the market today is Canon's GX1 - which is oddly about the only camera from the Canon range that I'd recommend!

The Nikon D3000 with the 18-55mm Nikon lens for about $460.
The Nikon D5000 with the 18-55mm Nikon lens for about $640.