I live in an urban area so my everyday carry knife is a large SAK with a locking blade. I use it almost daily for opening letters, opening boxes and small repairs. The SAK seems a pretty good choice for that. I have a Leatherman Wave but don't carry it nearly as often. It has many more functions than a SAK and I love it but most of the time all I need is a knife blade and the one on the Wave just isn't that good.

Outdoors I tend to use a knife a lot more and for heavier tasks. These days it's my Kabar most of the time. It sees a lot of use, mainly carving wood, preparing shelter poles or a walking staff, making fire (with a magnesium firestarter), cutting twine etc. On shorter daytrips I can do most of the chores with a smaller Scandinavian fixed blade or even just my SAK, but on longer trips I really appreciate having a larger sheath knife.

One time when I was stuck in the middle of a steep icy slope I actually had to use my Kabar as an ice pick. I'm glad I carried it that day, I can't imagine getting out of that situation with anything smaller or less robust.