In the beginning there was the GeForce 8800 GT, and we were happy.
Then, we then got a faster version: the 8800 GTS 512MB. It was more expensive, but we were still happy.
And then it got complicated.
The original 8800 GT, well, it became the 9800 GT. Then they overclocked the 8800 GTS and it turned into the 9800 GTX. Now this made sense, but only if you ignored the whole this was an 8800 GT to begin with thing.
The trip gets a little more trippy when you look at what happened on the eve of the Radeon HD 4850 launch. NVIDIA introduced a slightly faster version of the 9800 GTX called the 9800 GTX+. Note that this was the smallest name change in the timeline up to this point, but it was the biggest design change; this mild overclock was enabled by a die shrink to 55nm.
All of that brings us to today where NVIDIA is taking the 9800 GTX+ and calling it a GeForce GTS 250.