If by the image you gave, the air flow means having the case open, then I am due some royalties.
I used to keep up with how to build a PC yonks ago and I would like to do it again if only to ensure I get precisely what I pay for. However keeping up with the hottest tech hardware in any field is a losing battle. As soon as you acquire the best on the market, the next thing comes out. Unless you work for NSA, CIA, SS, or the international equivalent you will NEVER own a rig that will not be at least partially obsolete in two years.
I still run a mostly pre-set Dell with a few upgrades and the fool thing has been pretty much bullet-proof for all the junk I've given it. So, in the field of ready made rigs, it's not so bad, and you can always adapt them if you have the gumption to do so.
The best upgrade I made to my rig was going to Windows 7 from Vista. However that does not count as an upgrade since getting rid of Vista in any fashion is really a reset to OEM.