So my usual answer to this question (for basic exploratory analyses with project teams) is to use R to make extremely high resolution 36x42in (or whatever) plots of the data and then print them using our map plotter and hang them on the wall. This allows us to quickly draw and annotate on them when we are working with the data. It also helps overcome powerpoint's little resolution problem (and more generally, the lack of resolution inherent to most business class projectors).

If I'm showing lots of high resolution plots, I generally favor using something like windows picture viewer over PowerPoint, because I can use one high resolution graph and zoom in the relevant sections as I discuss.

I've been playing around with things like the threejs plugin for QGIS and the dygraphs package for R to generate self-contained, dynamic, and/or 3D visualizations for management. This gives a "wow" factor and keeps management from falling asleep during a data heavy presentation - and the dygraphs or threejs maps can be recycled to my project teams for their casual use.

The resolution problem is one I struggle with frequently. I want to show 10 years of time series data at 12 locations at once and highlight the relationships between time series - doing that with enough detail and clarity to be useful is a big issue for me. The usual answer is either: really big high-red plot (maintains "connections" in the data but can be difficult to interpret and use during a presentation) or lots of lower resolution plots that window in on certain interesting phenomenon (easier to interpret but chops up the data and implies separate, rather than interconnect, phenomenon)