You know you might want to cancel that order again
Look here:
http://store.apple.com/us/browse/home/specialdeals/mac
This is the refurbished section of the apple store. These machines are pretty much brand new. Some people say they are better than the ones you buy normally because they had been tested down to every little component and anything that is not 100% is replaced. I Have several refurbs and they are flawless.
Any way, you can get a 3.4 i7 for less than what you paid for your 3.1 i5

or you can get the 3.1 for pretty much the same price as the 2.7 i5.
You might want to look at that and reconsider. Im amazed no one else brought up the refurb models.