While I agree wholeheartedly with the sentiments about the cash/visa would be useful so the kids can do with it what they want, the OP is looking for something she feels is thoughtful, and perhaps something her adult children would not, for whatever reason, buy for themselves at this time. I know that is what I like to think of as gifts for and from myself.
The OP I am sure would know if the kids were in such a finical hardship that the money would be better than a gift.
I love all things Apple. In my house, we have two Macs, my iPhone, a few iPod touches, an AppleTV, and even my wireless routers are Apple. The one product line I do not yet have is an iPad. The reason is that, for me now, the cost to purchase is not justifiable. I am currently paying a few things off much sooner than the "plans" allow, so I make some "sacrifices" to do so.
However, if my mom bought me an iPad? I would be thrilled. Not that I wouldn't be thrilled with a check or gift card for $1000, even if the intent was for me to purchase the iPad. I just know I would put it toward something else I was going to pay anyway.