Excel is my go-to tool for data visualization. Everyone I work with is familiar with Excel, so that has been the easiest to use especially when it comes to collaborating on visuals and having it modified by the comms team. Lately I’ve been exploring visualizers for qualitative data. I find Excel is really good with that too (heat maps – see Jennifer Lyons’ Qualitative Chart Chooser). Besides Excel, I like to use Gephi for network mapping and have been learning some tricks in R.