"It's none of my business but that never stopped me."
Remember that the 12-yr-old will be 13 next year and probably of the gamer mentality of present 13 yo. and the 11 yo .......... Buying for this year, not for next year and the next would seem to ensure rapid replacement. But laptops will be out-of-date pretty fast.
Desktops are so much cheaper and are upgradable that you'd have to do a lot of talking to convince me that laptops make sense.
That said, I use a low-end laptop as my main machine - 512 Mby RAM, 40 Gby HD, but always use an external mouse. I like the fact that its fan is much quieter than my old desktop. I use an external keyboard when at home. So there's still a bit of clutter and wiring. It would be entirely inadequate for gaming. My use is net access and software development. Neither strain the display. A desktop w/ LCD display wouldn't take much more desk space
and would be a lot more durable.
Buy desktops today. Save enough money to buy laptops later when mobility is important. You'll probably find you'll only want to buy one laptop a year as the kids get old and hand-me-down the older ones. A laptop bought today will be graded "useless" by your older kids three years from now.
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