Top Steels
I have a several blades in stainless of one kind or another.
Some of them, however, seem to be a step up from the others.
440C and 420HC perform well and hold an edge. After good heat treat they seem to perform at a similar level. I believe I also have one in 425M, which is more or less on a par with them.
S30V, ATS34, and 154CM are premium steels. I don't have a lot of those, but the ones I have were fairly pricey and worth the money.
My favorite, though is an in-between steel family, the Sandvik 12c27 and 13c26 steels. They don't rust, they take and hold a really good edge, and they're not too hard for field sharpening. My EKA, Mora, and assorted Finnish blades all seem to be made of this stuff. I have recently added a Buck Vantage Avid to my stable o' steel, and it also uses the Sandvik steel.
I've never done a hardness/durability test of CV, D2, or any of the other carbon steels against the premium stainless grades, but I would be very interested in seeing such a comparison.
For generations it's almost been a truism that the carbon steels would consistently outperform the stainless stuff, but with the advent of formulations like ATS34, S30V, 154CM, and their cousins, especially with heat treatment like Paul Bos' method, I'd imagine that stainless is no longer "second chair" in performance.
I'll bet someone (like hso) has a table that rates the comparative merits of the stainless vs carbon steel families.