I refuse to pick just one and toy can' make me.
Two maybe, my Grandfathers Polish Pruner because after not seein' it for 30 years, (the last time I saw my Grandfather), my cousin saved and gave it to me a few years back when I took my daughter to Hungary to see our family, (I'll never forget how my Grandfather always had it with him and use it to slice pieces of smoked meat, some veggies, and bread from the pantry to make us a snack/lunch in the afternoon.
The second would be the '08 Forums knife ,Northwoods medium Stockman, I just love this knife ad wuldn't give it up for anything.