I'm still concearned with the price.
I hate console gaming, but seriously.
2 7800 GTX in SLI - ~ $1000-$1200
1 AGEIA Physics PPU - ~$300
You are looking at upwards of $1500 if you want high end, and if they are all replaced in 6 months, that is a ton of cash to drop simply to game at the top for 6 months.
Granted it will all last longer, but still thats a heavy premium to pay for such short product cycles.
Also for the more main stream gamer, those with cards in the Graphics cards in the $150-$250 range convincing them they should drop another $300 on a PPU when the $250 GPU was already taxing their budget is ridiculous.
I know this is cutting edge tech, but even AGEIA has to realize that GPU's slowly worked their way up.. initially Voodoo cards were $100-$150... only recently has this trend of pricey video cards caught on. Had 3dfx started with $300 cards.... 3D gaming as we know it today would not exist.