I would tread lightly deleting folders you don't understand. I mean there are printer drivers you can dump for a quick 3 gig and you are considering going after something when you don't know the consequences?
I admit 21 gig is a tempting "payback" but I'd investigate more before you pull the trigger.
Why are you trying to free up disk space? It wouldn't be Lion related would it? Or are you trying to shoehorn your boot drive onto one of those less expensive SSDs? I have found it's a lot safer to move things like your iphoto library or itunes music to a firewire or usb drive. Just be careful moving the iphoto library. If your only copies of photos are in there, which they should not be, you run the risk that you break something by moving the file. What I've done now is put my photos on an external drive and when I add them to iPhoto, I uncheck the option to copy them to iPhoto library. Now I have an iPhoto library that is less than 1/20 the size of the photos I'm organizing. When you consider that I've got over 100 gig of photos being indexed, that's a good thing. Of course this means you can't go around willy nilly moving your photos around after you've added them to iPhoto or you risk losing links to metadata you've created such as events, faces and places.
