Helium. It's colorless, odorless, tasteless, non-toxic, inert, and useful in everything from better hard drives to laser fusion power. Given these incredibly handy properties and helium's finite supply on Earth, scientists really wish we'd all stop wasting it in balloons already.
Most of today's non-solid state hard drives run on air. The read/write heads "surf" above the frantically spinning magnetic platters on a cushion of that breathable stuff, but the downside is that the heads bumble around a lot in all the turbulence. Western Digital is about to replace all that air with helium, massively increasing drive performance.