This post would suggest you'd get 200-300 MH/s per card.

You can use a profit calculator to see if you break even. You need to look at total power costs as well. However with more ASICs coming online you will find it hard to make a profit. Look at mining Litecoin and using cudaMiner.

At current difficulty, 500 MH/s would produce an average of BTC0.85 a month before costs.

For reference, a ~BTC10 equivalent personal loan from my bank for 12 months would be charged at 29.9% APR, and bear in mind they know where I live, how much I earn and (more importantly for them) they have the legal resources to chase up their repayments.

10% less for a more risky venture doesn't sound very appealing.

Vircurex lets you exchange Bitcoin, Namecoin, Devcoin, Litecoin, Ixcoin, PPCoin and Terracoin.

At the current exchange rate I'm paying just over $0.15/kWh (10.301p/kWh).

There are so called Economy 7 tariffs here where electricity is half-price between midnight and 7am, but whether that works out cheaper for 24 hour mining operations or not, I don't know.