OMG…I knew they compiled Windows on Mac G5s. I KNEW it!! 
Why do you think we acquired VPC? 
One of the benefits of making the whole widget is that you can take things like how to get rid of the heat into consideration. Macs are usually textbook examples of good design. They don’t just look pretty, the insides work well too.
One of the things that helps both stability and longevity in the processors is that they usually don’t run them at the edge of their clock speeds. Apple tries to find the sweet spot between performance and stability. While many consumers don’t seem to get it, Apple knows that clock speed is not the end all and be all.
The “megahertz gap” that people often cite with Macs vs. PCs doesn’t really have much to do with how effective the processor is anyway. For a PC vs. PC example, Intel chips running at around 1.5 the clock speed of an AMD processor do better than the AMD only when doing many different tasks at once, and then only when hyper-threading technology is taken advantage of.
Years ago I read a book about the history of Apple (West of Eden). When they were developing the Apple II Steve Jobs was absolutely, positively, fanatically adament that it would NOT, under any circumstances, contain a cooling fan. Noisy fans were the tools of stuffy, IBM suits.
Seems a bit silly to me today. Though I am a lifelong, diehard, real-men-use-PCs-and-Macs-are-gay type… 
Despite being a Mac-first guy, and definitely not gay, I seem to get the same impression from people on the internet. It seems like most of the Mac users are vegetarian, leftist-quasi-communist, tree-hugging, free-love, Bush-hating, weird-dressing, body-piercing, anti-war, SUV-hating, hippy types.
Despite impressions, please be cognizant that I’m at least one Mac-firster that’s the complete opposite of all of that!
A pleasure to have you on our boards, Mr. Limbaugh. 
James Lileks is a right-leaning Mac user, but overall it does seem like the majority of Mac users are on the left end of the political spectrum. My theory is that using an OS with a fairly small customer base probably appeals to people with counter-culture/anti-establishment leanings.