I usually carry more than one knife at a time on me, usually one plain edge and one or two combo's.
I prefer a combo more than any blade edge mainly because you have both available in one package and at hand. Cutting through cardboard, rope, wire, etc., you can't beat the serrated edge. For all other cutting I like the plain edge.
An all serrated blade, I don't care for and don't have ANY either. You are limited with just serrations, rather have an all plain edge if a combo wasn't available.
Right now I have on my person the Mission MPF1-Ti (combo edge), the MicroTech SOCOM M/A (plain edge), and in my jacket the Cold Steel Gunsite Folder (combo edge).
I do switch off and on, especially on the weekends. Got too many favorites to not want to carry and use. Yesterday I had on me my Emerson Commander and my Spyderco Military along with Gunsite Folder.
When I get my REKAT SIFU, I will probably replace my Cold Steel Gunsite Folder with this one as an every day carry. Who knows, maybe it will replace others off an on as well, time will tell on that!
So in my view, I would rather have a combo edge followed by a plain edge, but I never want an all serrated edge on a knife.
Mark
[This message has been edited by Mark W Douglas (edited 21 April 1999).]