Well, if they're buying 3-5 Xboxes, their intelligence is already suspect...
I paid full price for my first 360, and it was stolen. The next one was a broken one I traded some junk to Doug for and swapped. The other two I have are broken ones given to me for free.
My PC isn't "high end" (3.6ghz quad, 8gb ram, mid-range video...radeon 4850), but I can play all the games on it as long as I don't try to max out settings.
Either way, there's shit on the 360 that isn't on PC. Stuff that I like to play. Xbox Live > any other online game/movie portal. Burning a 360 game to a $1 disc > downloading a PC game and worrying about patches/cracks/serials/updates/viruses/peniswhistles. Also a lot of PC games are starting to get rid of dedicated servers so you HAVE to connect to theirs and thus HAVE to buy the game to be allowed to connect. 360? Burn it and it's fully functional without any extra effort. No pesky installations and the games always run smoothly.
I do occasionally buy downloadable content, but it's a small price to pay IMO.
I'm kinda pissed that Sony/MS are trying to drag out these consoles for another few years. My $150 midrange video card purchased 1.5 years ago has better graphics, but oh well.