The iPad will sell like hotcakes and while some preach doomsday for freedom others will make millions developing for it.
At the end, pops and moms will be happier than ever with their new computing experience that doesn't crash every day and has to be formatted and reinstalled every other month.
"Hi mum. Plug your iPad into iTunes and click 'add device to authorized list' under the Advanced menu when dad is logged into his iTunes account."
That one actually isn't too hard to walk people through on the phone. I did it with my mom and dad for their iPod's a few months back. Took all of five minutes; most of which was waiting for the iPod's to finish syncing.
My dad uses his GPS software almost every day (his GPS has Windows software) and likes 1st person shooters. My mom uses her quilting software almost every day. My uncle, a farmer in Iowa, uses QuickBooks for accounting. People have shelves of software that they use/love even if they aren't fans of Windows or OS X. Presuming they buy an iPad and lug their Windows boxes (which neither crash every day nor require reinstallation every month) to the garage, what are they going to do to?
Eventually there might be good software to fill up these niches, but it's going to take quite a while. And people will constantly be assailed with web sites and software boxes that have GOOD SOFTWARE that they can't put on an iPad. The App Store Apple is competing against is the rest of the world--- millions of Apps (some of which are really good!) and gazillions in marketing dollars.
That's why Apple (so far, at least) talks about iPad exclusively in the context of being an addition to a PC or Mac. In fact, it requires a computer for backup and OS upgrades.
The fact that your mom can't run her quilting software on it (so far) doesn't mean it can't do all the other things well and be a very welcome addition to her life. It just means she has to keep using her PC for quilting. At least until somebody realizes there's an opportunity for a good quilting app.
At the end, pops and moms will be happier than ever with their new computing experience that doesn't crash every day and has to be formatted and reinstalled every other month.