I know comparing Mac vs PC to religion is cliche, but folks, if I posted a message asking how to convert my father to Christianity or Buddhism or Mormonism or whatever, I'd be inviting all kinds of flames about religious intolerance.
The bottom line is that if someone is happy with what they have (or stubbornly refusing to consider alternatives) it is NOT your job to "convert" them against their will.
Some strategies posted here are good. The best strategy is to find a way to make your Mac "lifestyle" look so appealing, especially in comparison to what he's got now, that HE comes to the conclusion that "Wow, that does look better, maybe I should check it out." The critical thing is that HE makes that decision. Shoving it in his face and saying, "See? It's better!" is NOT the way to go.
(And yes, I believe that applies equally to computing platform as it does to religious lifestyle
)
So, demonstrate movies or slideshows you made with iLife. If they need help with making a slideshow, burn them a DVD that will knock their socks off and make them ask you, "HOW did you do this?!" Give them a Photo Book you made with iPhoto for Christmas. Bring over your Mac and when you show them web pages or YouTube videos, throw in a gratuitous use of Expose or Dashboard. Make reference to how your Time Machine backup saved the day last week. Bring over your iPod when you visit. But stop short of saying, "See, now if YOU had this..."
Denying IT services to your aging parents just so they'll switch to YOUR platform of choice seems cruel to me, especially if you DO have the technical wherewithal to provide them with support. I help my dad with his Windows PCs all the time, although I CAN truthfully say that there are certain issues that I no longer know how to address because I haven't dealt with them ever since I switched to the Mac.
Edit: Apparently I win the thread. W00t!
