Carbon if you care about your knife - stainless if you are careless with your knife.....that is what I was taught....but I prefer stainless if I am around water - especially salt water - as then I do not have to care too much
Generally I find that a carbon blade has more "soul" or "character" and is "alive" wheras stainless blades are purely "functional"...
Cor - that sounds pretentious!
However - most of my knives are carbon with wod handles (mainly un-stabilized) and with hand made sheaths.
I am not a fan of stainless steel blades, plastic (including Micarta) or plasticised wood handles, plastic sheaths - though they are more "advanced and durable" than my choice...they just feel "dead" to me - no matter how good a tool they make.... I also like Ventile, canvas, wool and leather gear more than synthetics
But then I have been told I am wierd in many other ways as well.....