Do we know the minimum requirement to play this game?
I would be surprised if my computer is powerfull enough for Skyrim

Nvidia 9600, cpu i6700, 2gram and Vista 32.

No. Your computer is probably fine, though, seeing how 5 year old hardware will be able to play the game.

As impressive as the screenshots we've been seeing are, they're not so impressive that the game looks unoptimized to a trained eye. It's even possible that it may run faster than Oblivion if they're optimizing it as well as they say they are. Also if you break the graphics down into it's individual components (fog, lighting, etc..) there isn't really much that's been added graphically that wasn't in Oblivion, aside from shadows which we already see in other games that run fine on similar hardware, and the fog effects on the mountains which are just fancy particle effects. The snow accumulation effects are a bit of a mystery but I think it's just clever use of multiple texture layers.