Not to flame you or anything cc48510, but a 128bit, 133MHz bus is pretty damn fast. Keep in mind that most PII/PIII systems are running 100 or 133 MHz bus, but their data path is only 32 bit. The Mac in this example is moving 4x the data per clock cycle. That is significant. Modern DDR and RAMBUS systems do give these systems quite a boost, but they are still moving data 32 bits at a time.
Now mind you, I'm still not buying a Mac. I have never seen any proof they run faster in anything other than programs it is optimized for, such as Photoshop (and other Adobe apps). I do not use these programs enough to justify the price differential.
More intensive maintence wise, 76? I don't see it. I've been running the same system for about three years now with no maintence to the hardware and software maintence only to fix things I screwed up. The mac is likely more idiot-proof, I will say that, but in the hands of an experienced user, there is no reason you cannot get years of service out of a PC without having to screw with it. Hell, my old man can do it and he's damn near terrified of technology...