I never really bothered till recently.  My desktop is now encrypted, though I should probably encrypt my servers too as that's where all the data actually is.  wonder what kind of performance hit I'd get if I did the servers though including data luns. Suppose if I do it right at the file system level on the file server, so the file server does all the processing, and not each individual VM it probably would not be too bad.  I do want to look at fully restructuring my storage/vm network one of these days, so it's something to consider.  I really need to come up with some kind of console setup for my server room though, as if I encrypted the servers it would require physical intervention to turn them on if they need to be turned off for any reason.  Right now it's pretty much the thing of praying that they come back up.  Rackmount consoles are freaking expensive, like several grand.  I'm not paying that for a monitor and keyboard.  Might have to rig something myself and while I'm at it, do a full KVM.
Of course, you also need a key that is secure enough, and that you can actually remember.  It's not something you need to type in often so the remember part may be tricky.   Suppose you could write it down in some rather cryptic way on a small piece of paper, and store it in a bank lock box and maybe somewhere in the house.  Like a grid of random characters and all you need to remember is the pattern.
The one I have for my desktop is not really that complicated, but it's just enough to say I have some basic level of security.  I'm sure the government would be able to crack it within a day with their supercomputers.