Really can't go wrong with any of the quality modern knives being made today. Used to be any knife would last a good long time, and with the advances in materials and manufacturing, knife lifetimes are expanding greatly. Of course, any knife a knife knut owns will receive relatively little use, overall, as said person will have more than a few to spread out the use with, and generally, folks don't use knives as often, or as hard as they used to. There are exceptions, though.
I would personally recommend a William Henry knife that would spend it's life doing gentlemen's work. Most likely, it would be with you for the important times, like weddings, graduations, parties, and other formal events, and would therefore have a good collection of associated memories.
Conversely, I'd also recommend a good sturdy ZT, Benchmade, or Spyderco, or other heavy duty knife, even consider a Buck 110, or GEC traditional, as a hard-use knife. These will hold up, and have the character developed during those "life happens" moments you would spend with your kids and grand-kids, fishing, working in the yard, fixing up the house, or car, and generally making more shared memories.
By having a few EDC and Special Carry knives, that you routinely rotate through, each grandkid will have the chance to own a piece of cutlery that will remind them of you.
My personal "Heirloom Knives" would have to be my Microtech LCC D/A, Benchmade 730CFHS, William Henry Gentac, Bose/Case Lanny's Clip, A. G. Russell Gent's liner-lock, and my GEC Bladeforums traditionals.
