I suggest the keeping the Core i5-2500K in your build because it might outlast any other option in the near future (esp when oc'ed) at that price point. I'd personally use a Core i5-3570K Ivy though, but it is a few bucks more.
If you need to spend less on a mobo, I think perhaps this ASRock
might work. In general, most people will suggest an ASUS of Gigabyte, but those boards will start around $100 or so.
I'm certain you can get a smaller PSU, something in the 500-600 watt range like this Antec
and save there.
Imho, splurge on the case to your liking because that is what you will see
If it makes sense to you, get a smaller 90 gb SSD. They have been priced to move at about $65 lately.
By strategic if possible - have a wish list and buy stuff of sale.
Lastly, the less you spend on your build, the more chance it will become obsolete sooner. For example, if you get that 750w Corsair PSU suggested in the MaxPC article, you will probably be able to recycle it for your next build or for another pc. The 550w Antec I linked to may not last past this build.