I think all of the hardcore computer nerd dudes are way, WAY over exaggerating the reliability issues with oem type computers, as well as not factoring in every little nugget of spending required to actually build a box if they have done it before or "have parts" lying around.
Poor oem cooling? lol. The guy is building a solid works station, not some mad tite 20,000 3dmark2020 gaming rig. Obviously for the HD situation, you'd try to find one that came with a 7200rpm HD, but any computer I've bought off the shelf has had a 7200 in it, it's not like they are hard to find.
Getting by with 4gb's of ram? Oh noez, throw another 4gb stick in for $20. Anyone who thinks they need 16gb of ram besides for mental masturbation is, well, ya... sure, it HELPS, but 8gbs is nothing to sneeze at.
As for junk with the oem software, they are just programs, you go "uninstall" and they magically disappear! It's not like they are hidden, and if they are, I don't know which oem's you are buying from.
Nice power supplies for a regular old gpu (SOLIDWORKS DO YOU PEOPLE NOT READ?!) and an extra HDD/peripherals is $25. The motherboard has built in gpu? Oh the horror, plug in your new $50gpu, it automatically turns the onboard off and you are good to go.
You guys are too focused on gaming stations/professional level work stations. Yes, he is using solidworks, but what I have described is a perfectly legitimate route to take, AND THE EASIEST. I don't expect everyone to be able to build their own computer, just like I don't expect everyone to have the skills to compete in the $2XXX GRM Challenege. Anybody can slam some ram and a psu into a computer though.