Great, or not so great for that matter as well, new visualisations that make me wonder and get interested in the data or information lying behind. These things inspire me immensly. Like http://hint.fm/luscious/warm-glow.html. No idea what the use is meant to be, but it gets me thinking, and lures me in to think of the use we could have, like in corporate communications differentiation situations and the thoughts rumble on. http://benfry.com/genomevalence/ is also one of those things you just cannot rub out of your head. No idea how to read it or even begin to approach the information. But completely to die for and inspirational in a fundamentally mindboggling way.
So I guess what really gets me going is the bright new ones with no obvious reason for existing until the user or situation makes the reason appear. Out of nothing.