Just a thought. Consider an AMD FX 8350 or 8370. These are often criticised for not being as good as an Intel CPU for gaming, but in reality things are not so simple. The price and speed of an AMD build with this chip and a good ASUS mobo will compete well with your suggested i5 3570 in single/dual core gaming (though there will always be some games that favour AMD or Intel for no discernable reason). When doing stuff that uses the full 8 cores however, the FX 8350/70 will be beating off many an i7. As games get more multi-cored (not a fast process, but many are wanting 4 cores these days) the AMD chips may well show a longer useful lifespan before upgrade is needed as well, so if you aren't the sort to upgrade regularly to the latest and greatest you may appreciate that.
Not a system for everyone, but well worth considering.
Also, 16gig of ram is worth considering now. That way you can get a matched pair of sticks and won't have to run mismatched sticks when you feel the need to expand. If you use a Crucial SSD in the build as I do you can leverage that ram with their speedy caching driver and you will have to wear flight goggles.
Additionally, contrary to comments earlier in this thread, AMD change their socket types in an incompatible way very infrequently. They just bolt on. The AM3+ socket is newest but my old AM2 ran all AM2+ CPUs and lasted through three major CPU upgrades well.