"netbooks: more versatile, better for content creation due to keyboard, games less immersive, crappy build quality, flash, malware a real risk, relatively complex to use"
You're writing "complex to use" and "malware a real risk" as if this is a novice PC user. Having a desktop and laptop I feel sure that (apart from using Windows 7 compared with XP or Vista) the user of two PCs will be able to cope with anything a netbook or laptop throws up at them in terms of learning and knows about tools to guard against malware (perhaps not living in an Apple 'ivory tower' believing it will never happen!)
As for games - depends whether the family like games they already play and can continue with them, or learning new ones. You may not get the latest high processor dependent blockbuster, but it isn't being bought as a gaming (only) machine, after all.
I can see that flagging may succumb to the lure of the iPad, which is "pretty" I have no doubt. It also has plenty of Apps available, so perhaps the family needs will be met. Having an iPhone already may also make it slightly more palatable despite any high cost. That's down to budget considerations which I don't wish to be privy to, but if I was spending cash on something to take away on a holiday trip, I think I'd prefer to take a slightly less 'desirable' notebook than a 'highly desirable' iPad, and if the worst happened, and it was broken (rather than stolen) then it would be a much lower sum of cash that had been put into it and all the more easy to replace even if not covered by insurance. If it was only ever going to be used at home, then I'd see significantly lower risk and if it suited the family need and budget, give it higher consideration.
They don't all have "crappy build quality" but are often built "down to a price" because there is a lot of competition where Apple just slaps whatever price it wants on a product and fans pay it (or save up and pay it). While some argue that Apple is overpriced, for other people it is "what the market affords".
I remember a comparison of the cost of the same brand of toothpaste in Brazil and France some 10+ years ago and there was at least a tenfold difference, because Brazilian consumers could not/would not pay the higher cost. I won't pay more than 8 quid for a CD, or more than 35 quid to get into a gig, because I consider that higher prices to be taking money off people who don't appreciate that paying more tends to make the sellers expect even more in future, and I decide with my wallet (and while I may miss out on some things, I don't regret it one instant). Similarly I will not buy Apple products at current prices. I don't expect them to go down anytime soon, so I do without, or have bought some (quite dated) items second hand, and never spent more than 50 quid. If one looks on Ebay, a fast XP desktop can be had for under 125 quid, so flagging could afford a netbook and to replace the desktop, for perhaps less than the cost of an iPad (do they still start at about 500 quid?)