So I have calculated all the expenses, savings, taxes, shipping, etc on what I would spend on both the 13.3" MBP i5 with an upgraded 500GB harddrive and the 13.3" MBP i7. My figures are: $1310 for the MBP i5 500GB, and $1520 for the MBP i7. So my question is how substantial of a difference is the i7 over the i5 and is it worth the extra $210?