Sometimes I think about possible analysis using GIS models (I use QGIS 1.8), and I always think about few types of visualization techniques: demographics, traffic flows, distance ones.
I discover many possible criteria (and I begin to use it) analysis and I like to collect the most important one in a single item to help the consultation.
Is this a good idea or not?
I try with some examples of a project where I worked on

generated traffic by zone by magnitude

traffic IN/OUT zone by zone by bar diagram

journey time on different routes

OD from a zone (Flow Mapper plugin from How to create desire lines in QGIS?)

quantity and quality parks on links