Most near and dear to my heart is a Marlin Model 99-M1 .22lr, built in the 60's, handed down from my grandpa to my dad to me. It's basically a Marlin 60 action, but with a 10rnd tube, and stock to look like a small M-1 Carbine.
It originally came with a rear sight that mounted on the scope dovetail, but grandpa lost it sometime in the 70's, so dad always used it with a scope. When I got it in the 90's, I took the scope off of it because I was using it for coons over hounds at night, needing an open sight. I used to aim by indexing the top groove of the handguard against the front sight, until the front sight fell off around 2000. Since then, I've been shooting it with no sights. Funny thing is, I can still shoot it just about as well as I ever have been able.
It's funny to think that it was "just a rifle" to them, but how it's become an heirloom to me, that I'll pass down to my boys someday. Grandpa and dad didn't take very good care of it, so it has some pitting, a ton of scratches, and the stock looks like he11, but if there's ONE rifle I'd never part with, that'd be the one.
If I didn't have boys to pass it on, I'd have it buried with me.