I'm guessing the GPUCoin price will be pretty close to what it costs to mine. If you have to pay more than the graphics card's price you want to buy - in electricity costs - it doesn't make much sense to mine, right?
You bring up a good point about the power costs. Actually, I had totally forgotten about the power cost to be honest. So let's toss out some data. I can personally ScryptN at around 10Mh, and it will use 7,000w/hr. If I mine for 24 hours, that's 168Kwh. If my Kwh cost is 0.11/usd, then my mining cost was around $18.50 for a day.
Speculation:
Let's say it takes 7 days to mine enough GPUC for a 270 series card. I spent $130 to pay for the electric. How much is GPUC worth at that point? The longer I have to mine for a card, the less perceived market value the coin may have based on electrical costs, because at some point electric will cost more than just buying the card outright.
Perspective:
I can get MSI R9 270's on Amazon for $150 fiat (last week's order).
This would demand GPUC be worth much, much more than it is now.
And when the price is so hight that it would become profitable to mine them for GPU, I could simply cashout and buy a stack of ASICs to mine litecoin or one of the 1000 altcoins, lowering my electricity cost by factor of 10...