Everything you need to know is in there.
Now if you are doing an upgrade and are keeping general things like HD's, DVD drives, case, P/S, etc. then this is what I would do:
Core I5 - K series for overclocking
Pick a good heatsink from www.frostytech.com
Make sure your current case and P/S can handle the new load and all the new stuff going into it.
Get a GOOD P/S if yours is a no name brand or al cheapo.
(I have a good case and P/S so I'm not worried about it.)
Any DVD drive is fine (I'll keep my old one)
HD's if you are not using a WD Caviar Black 1TB, or Samsund Spinoint F3 tb get one. (I already have 2)
Use TR's recommend mainboard, ram, etc.
Go with Radeon 7870 or equivalent Nvidia
If you already have a 22" to 24" monitor, keep it, (or if you are happy with what you have even if it is bit smaller)
then finally add a caching SSd such as this: »www.newegg.com/Product/Product.a···20171667
Total upgrade will be about $800 depending on what and where you decide to spend.
Your videocard is going to have bigger impact on games than processor. Don't skimp on the card.