I've got two SAKs that were both given to me by my father. They're very important to me, and in fact I've carried one or the other - always kept sharp as a razor - on me since about the age of 7. They're both the same type - the Spartan. One is red and one black, the black one being slightly newer and having the toothpick and tweezers. I didn't get the black one until I was 15 or so.
The plastic handles are quite worn on both at this point, and the blades on the red one have been sharpened probably a couple hundred times by now (thankfully, I was taught how to sharpen properly, so I've not over-sharpened them over the years). They've been used to open dozens (hundreds?) bottles of wine, and untold bottles of beer (both for me and others). I've gotten good use out of them (and don't agree with the statement here that they're 'soft' knives - only if you don't sharpen them right are they; they're fairly strong steel).
My view is that knives are supposed to be used, so I do just that. They've got sentimental value to some degree, yes, but I don't put it over their utility. I usually carry an additional blade along with me - a lockback carbon steel Schrade, preferably, given to me by my grandfather - when I suspect I'll have more use for a second blade.
However.
I can understand where you're coming from, certainly. When I was about 8 or 9, my dad gave me a very special knife. It was small, very small - maybe an inch and a half in closed length, with two fold-out blades. Its handle was made of mother of perl. I can't really understand why he gave it to me; it had been his grandfather's knife, given to him by his dad. I can only assume it's because he saw my fascination and wanted to show he cared for me. It was appreciated.
At any rate, I took the knife with me on a fishing trip down the hill to the pond on a rainy afternoon. I actually took all 4 of my knives, and a bunch of other stuff - I've always been a bit of a packrat and the "hey, I might need it" type. Long story short: I somehow managed to drop and lose the knife. I don't remember how; it may have fallen through a hole in my pocket, if I recall correctly. I looked for hours, and came back the next day to look for it. But I never found it. Since then, I've never lost a knife (permenantly), though I had a couple 'commando' style knives break on me, or incidentially confiscated by parents for cutting chunks out of things I shouldn't have.