I've never had any issues even close to this. My Mac laptop has been flung from its carrying case onto stone steps when the strap on a laptop bag broke. The casing chipped a little, but no performance issue.
I've only ever had 2 hardware issues with Macs, and one of them was our own fault. During an electrical storm my dad laughed in the face of good sense and left the machine plugged in and turned on. He wasn't laughing after the power surge! Actually everything worked fine except for the ethernet card, which was fried. This was a 1st Gen iMac, the little colored ones, and we still use it today. The other issue was for my g/f's iBook, purchased in 2004, which we had to purchase a new battery for a couple of month's ago.
When I ran my repair business I got lots of calls for repairs for MACs, most I could do nothing about unfortunately. I also got lots of calls for repairs for PCs, it ran about even. I never found one to be better built than the other, just found PCs easier to work on and repair.
Everyone has different experiences. As was just pointed out, some users are very happy with Vista and love it, others hate it. I know people that have had nothing but hardware problems with PCs, some who have had their MAC in for repairs a dozen times. Like anything else, everyone has their lemons I guess.
For me it always boiled down to usage. I would get calls from college students asking me to build them a cheap PC, instead I would turn them to MAC and they were always glad I did. Others needed a PC that did it all for the entire family and that is what they got. I built two customs for the church eight years ago and they are working perfectly to this day with no upgrades and no updates since they are not connected to the Internet. If they had the money I would have gotten them MACs since the Pastor knows nothing about PCs, would have been easier for him. Still, they meet his needs to this day.
I don't stand behind PCs 100%, but I wont stand behind MACs 100% either. Based on what Andy has indicated so far, I would suggest a MAC for him, I think it would do him just fine. But not even MAC will guarantee their product for as long as he owns it. I just don't want anyone making a decision based on misconceptions or partial information. For instance, reading up on complaints for Vista, seems to me a disproportionate number of them are coming from DELL users. So if Vista is running better on HP or other brands, then not all of the fault can fall on MS, some has to be passed on to DELL.
I can also say, after looking over the kids DELL computers, I am almost ready to cancel my DELL on order and go back to HP. HP is much better built and way more solid than their DELLs. It was not a good choice for a kids computer in retrospect.