You will regret building with an i3 if you want it to last more than a year or two. Of course, you can always upgrade to a locked i5 for a couple hundred bucks later.
Also, I have heard that the skylake i3 can get some pretty substantial performance gains when paired with higher bandwidth RAM. This probably means spending a bit more on both RAM and your MOBO. However, it could be the kind of small change that makes AAA titles like GTA V playable at decent fps.