I see the i7 is cheaper. So I understand the i7 is much better choise
In my own personal opinion I would wait until they have refined the technology of Intel i7 processor line. The i7 processors are 130 to 140 Watt. In the future I am sure they will bring the power consumption down to 95 Watts or lower.
The Intel Core 2 Quad Q9550, or the Q6600 are 95 Watt processors and great alternatives to the i7.
Lets not forget the performance boost vs cost is not quite there yet. i7 might be better but lets see some actually quad-support for games before we go upgrading too ^-^