My most used knife at work & as an EDC is my blacked out combo edge Native 5 Lightweight in S35VN. If I could have only one folding knife, I think it's what I would pick. Not because it's my "favourite" in a sentimental sense, and not because it's the best at everything, but because it is very capable at everything I need a folding knife for (the serrations are important because I cut a lot of rope & other fibrous materials at my job). In terms of overall folding knife utility, it's the one that works best for me.
I have folding knives that have similar work utility (Delica 4 combo edge), and I also have knives that are more corrosion resistant (Salt 2 SE, Tasman Salt 2 SE, Native 5 LW Salt PE), or that are more discreet & carryable (blacked out Li'l Native, Dragonfly 2, Chaparral FRN, Manbug SE), or have significantly better wear resistance (Native 5 LW S110V, Dragonfly 2 ZDP-189), or have more usable cutting edge (Polestar, Alcyone), or have better personal ergonomics (Introvert, UKPK, Yojimbo 2), or are better suited for SD tasks (Yojimbo 2, Introvert, Karahawk), or are "classier" (Native 5 G-10, Q Ball)—but while this particular Native 5 Lightweight doesn't score an "A+" in any single category except work utility, it's a solid "B" or "B+" across the rest of them.