To Serge or Not To Serge....that is my question

A while back I bought a serger, a Juno by Janome from Hancock Fabrics. I've played with it a few times and tried using it on a couple projects. My question is when do you use a serger? Are there hard and fast rules? Is(are) there a certain type(s) of fabric that are best? Should you only use it on the long straight stretches or can you use it for all seams? Do you need the different specialty feet? Do you have a favorite book that explains the world of serging to a newbie? I absolutely love the way my serged seams look but for now I think I'll stick to my regular machine.