yoyo5757 didn't mention in the original post which disk size he was thinking of getting, and there seems to be some evidence that the 128GB SSD may be slower than the 256GB/512GB drives, I'd still say upgrade the SSD to 256GB drive over an i7 or 8GB upgrade. 256GB storage would be a minimum for me.
That said the 128GB->256GB is $200, compared to $150 i5->i7 and $100 4GB->8GB so if you're on a budget this may not be an option.
That said the 128GB->256GB is $200, compared to $150 i5->i7 and $100 4GB->8GB so if you're on a budget this may not be an option.