After the last of my DeWalt 14 volt batteries died, I recently bit the bullet and upgraded to the 20 volt system. We have a set on the service truck at work and they usually find their way into the shop, too. I was hooked when I discovered that we were using the 20 volt electric tools (impact, driver, sawzall, drill, etc) far more than the air tools. In fact, they have truly become the tools of choice in *most* situations. We hardly ever fire up the compressor on the service truck and when we do, I have to stop for a moment and remember the procedure ... It's fussy in its old age (This isn't its first service truck

) A couple of tools I have that don't seem to have a cordless or electric analog (yet) are the blast cabinet, air inflator and the 1-inch drive impact.
I think that for a lot of us who have been in the hobby a while, the compressor and associated tools, are a sunk cost we don't even think about anymore. 20 years ago (and more), if you were halfway serious about this hobby, and were going to do more to your truck than just tune it once a year and change the oil, you just simply needed as big of a compressor as your budget would allow. I am truly impressed with how far the cordless tool technology and capability has improved over the past decade, so I don't think that thinking is completely valid anymore, as Bartamos posits.
My air-driven drill and air-driven ratchet are the two most useless tools in my shop. I gave up on the ratchet after the first attempt. And I don't use the drill as a drill. I mostly use it with a seaweed wheel.