My knife for boating/swimming is a fully serrated Spyderco Atlantic Salt. In that situation, where you end up cutting a lot of heavy lines, ropes, frozen fish, ect.....serrations can prove very useful.

Otherwise, the overall majority of my blades are plain edge. For general tasks I don't find serrations to be a necessity as long as my knife is kept sharp. If anything, I sometimes find them to be a hindrance.

If there is one company that I think does partially serrated blades right, it's Victorinox. They put the plain edge towards the back and the serrations towards the front. For some reason I find that arrangement to be much more practical.