I would suggest getting the i3 model, since you can most likely upgrade to an i5/7 cpu in the future if you need additional power, while you can't generally upgrade graphics cards.
The performance difference between i3 and i5 is fairly inconsequential if you don't do anything too computationally intensive, but you should be aware that if you do indeed perform some computationally expensive task on the computer, and it does not receive adequate cooling (such as if you block off the air vent), the core i3 model will throttle itself at about 10 to 20 degrees earlier than the core i5 model, which will result in a fairly large performance hit... although if you're not adequately cooling it, the i5 will probably throttle itself a few minutes later anyways.