when building from scratch, unless the IB i5 comes at a real low price MUCH cheaper than the cheapest Haswell i5, it's kinda recommended to go with the latest for a few dollars more with a bit more gain. but if you prefer to save that few dollars, than IB's the next best choice.
if this was an upgrade from Sandy Bridge, Haswell just isn't worth it. even if you have an 1156 i5, you may be better off waiting for the next gen of CPUs.
my i5-3330 + 670 build i currently have is only a few months old (before this an i5-2310+6870. GPU died, & i really felt like building from scratch), the cpu much slower than an i5-3470. despite being a real demanding game, ACIV runs great at the highest setting, though i doubt it's running at a solid 60fps. was it worth the money? yes. would i've been happier with Haswell? probably. did i regret not getting Haswell? NOPE.