daswilhelm :
$600 budget to compete with the next gen consoles? Hmm, keep saving. A gaming PC is only as good as the budget that you have, and for $600 you'll have a pretty basic machine (maybe a bit better then current gen consoles.) When you hit around $1000 - $1250 mark you'll be happier and have a much better build.
This is a rough outline for costs of PC parts. I'll assume you already have a Mouse, Keyboard and Monitor.
CPU (depending on brand, either AMD or Intel) $200 - ish.
Motherboard (Again, general price, not specific to any brand): $200 -ish (for higher quality models anyhow)
Case (general price, not specific to any brand): $60 - $100
Power Supply (general price, not specific to any brand but higher end): $80 - $120
Hard Drive (SSD, always good for a boot drive): $100 - $150.
Hard Drive (mechanical 1TB or so): $80
OS License: $120 or so
Minimal budget: $840
Not including whatever you would spend on a graphics card. So your budget just isn't there, yet.
you can build a solid gaming machine for around $600. no need to spend 200 on a motherboard. a decent power supply can be had for much less than 80. also no need for an SSD. and lastly, a GPU might be a good thing to add to the list, considering this is a gaming machine.
i have no idea why you think the "minimum" gaming machine would cost $840...
The site you quoted, even $750 is considered budget, not gaming. The problem with using the term "gaming machine" is that it's really subjective to the standards of the person using it. For me, I guess my standards are just higher than yours? I don't know.
But for ME the minimum gaming would be.
3570K Proc
Z77 Motherboard
CM Hyper 212+ or better (maybe liquid cooling)
Minimum 650W Corsair PSU (preferably modular)
8 GB DDR3 1866
Decent Case (Antec 302 is a good starting point)
120 GB SSD Drive for bootup and primary apps
1 TB Sata III mechanical drive for music and steam backups
Windows 7 OEM
And a Nvidia video card (I think the new 760's look pretty good, price is decent).
No way you're getting that for under $1200. If you can, I salute you.