Buy them tickets to see a show at the nearest major theater...you could even get them a gift card for Broadway shows! Other great "experiences": movie gift cards, restaurant gift cards, sporting events, dinner cruises or Netflix subscriptions.
Get them some of the gadgets that have made life a little easier in the years that have passed since they last bought similar products. Kitchen gadgets have made great gains; how about a handy Julienne slicer, like this one, from Williams-Sonoma?
Gardeners might enjoy garden labels, like this ceramic set from Terrain.
The whole family can make an appearance in this tidy little desk calendar from Pinhole Press.
And if you think they're ready to make the leap, I think grandparents are prime candidates for e-Readers. They can adjust the font, read as many books as they want and not have any more clutter. Pretty ideal. The Kindle 3G is $149 here.