I think powder steel as used by Falkniven in some of their more expensive knives is best. I have it in a pocket knife I carry and one fixed blade knife. It holds an edge very well and is easy to sharpen.
Personally carry a Benchmade mini barrage 154cm with an assisted open and it's decent for everyday use but if you want one that's truly universal and easy to sharpen holds a decent edge my vote is on Spyderco h1 it rockwells at 58-59 and will never rust