[SGVLUG] Where's the sweet spot these days for moderately fast PCs?

[Dan Kegel]

My Core 2 Duo systems are starting to feel slow (son
wants more FPS in minecraft, and I don't want to share
my i7 :-) so I'm looking for the sweet spot again.

Judging by http://www.cpubenchmark.net/cpu_list.php
the i5-2400 at $190 is 10% faster than my i7-920:
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115074

Another $10 gets another the i5-3450 and another 15% performance bump,
so that's probably the sweet spot.  Explains why
http://www.techspot.com/guides/229-desktop-buying-guide/page3.html
picked it for their "entry level" pc.

Then comes the choice of motherboard.
The i5 can be used with a $50 H61-based motherboard (UNLIKE the i7-920 !):
http://www.newegg.com/Product/Product.aspx?Item=N82E16813138332
A Z77-based motherboard goes for about $100, e.g.
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157306&Tpk=ASRock%20Z77%20Pro4-M
and has all sorts of whiz bang things like usb3 and pci-express3...
but I can't imagine any
of them would matter for my purposes.

So how far wrong can one go with an i5-3450 and an H61-based motherboard?