I would go for the i5 2009 i made the same decision and order two days ago when i saw the great prices you are paying basically £269 im in UK for the computer as screen is worth £1000 alone and based on what i use it for basic editing the quad core is faster than the i5 21.5" because it has 4 real cores instead of the equivalent virtual cores which is in the i5 21.5" and i also believe it will last longer and you can always upgrade ram in a few years to give it a boost. You will also want the 27" screen its just a piece of art if you can accommodate the 27" screen then i would always go for it.
You pay $70 LESS for the quad i7. Sure you could get the free iPod and sell it, make 135 on it and net about $70 over the quad i5 deal. But the quad i5 in the 27 is so much better than the one in the 21.5. It should be a no brainer. Get the refurb.