My personal preference is to generally use reflected light readings. These DO occasionally require that you understand what you are metering. If the scene doesn't have an "average" sort of reflectance, you should interpret this and make adjustments. For example, consider a backlit person standing in a doorway - do you want the face to have normal brightness (as in a portrait), or do you want the face to be darker to give the sense of being backlit?
Situations where I tend to use incident metering are limited. They would generally be where a "normal" sort of subject is mostly frontally lit, especially when the subjects are people (such as studio portraits). The incident meter won't be fooled by the color of the subject's clothing. For example, if you are photographing a bride and groom, you may realize that they both should get the same exposure setting. An incident meter gives this desired result. Had you used "average" reflected light readings of them individually, the black tux in one and the white dress in the other would cause the meter readings to vary.
Many people seem to prefer incident readings the majority of the time.
BTW, a few months before you joined, Mark Barendt wrote a pretty decent article on incident metering - it can be found here: http://www.apug.org/forums/forum216/...-metering.html