I carry the Spyderco Native FRN. The blade is made from S30V steel, which is fairly hard and holds a good edge. The blade is longer than 3", so it won't be legal in some places. I find it relatively unobtrusive for general use, being large enough to be effective yet small enough to go unnoticed. Light. Strong. The large thumb hole and reversible clip allows for ambidextrous usage. (Important for a lefty!) I would purchase another. It's listed at $75, but you can find them for under $50.
I have been considering a Benchmade 558-400 Griptilian ($107) but have not yet justified that it's significantly superior to the Native FRN.