IMHO, this thread of Mac vs PC is a little "off" in that we are comparing DIY PCs with Macs.
As there is no such thing as a DIY Mac, it's a little hard to compare "side by side".
Having the choice of your own components is due to the fact that it's DIY, not because it's a PC.
A closer comparison would be "branded" PCs to Macs. Now, I'm sure if you compare branded PCs to DIY PCs, one would not have much "change for meal and cab fare" left if one goes the branded PC way!

Of course, you have a choice to upgrade components for branded PCs, but so too with the Mac. However, I don't think the branded PC co. would cater to your request if you asked for a higher powered PSU, for example? There are some components the branded PC would not accede to change even if you asked for it. Lest it won't be "branded" anymore, I guess!
I use both platforms - the PC, out of necessity and the Mac, out of preference! :lol:
I recently started doing some training in a Mac lab, after 6 years being "out of the scene" from Macs (ie, 6 years of PC-only environment!).
I realized that there was a lot LESS requests from student participants, during training, about the "why-no-sound" syndrome in the Mac lab!! :lol: End result? The students were able to get a little more focused on learning the things they are supposed to do as opposed to "struggling" with the hardware!
Anyway, it's MY opinion only! :wink:
QF