I use the injinji toed socks. My main pair of Vibrams were the KOS, found that if I don't wear socks they would cut into my feet. The injinji are one of the lighter socks out there and they make them with different lengths. The compression version are interesting, but I think perfer just a compression sleeve to the socks. I like the low cut, but I guess my feet are of slightly different lengths cuz the low cuts feel a bit short on my right foot...I almost always wear socks with my vibrams, but ymmv...
I don't run in my VFF, but I wear them around the house and for errands. I have the ultra thin Injini toe socks for wearing with my VFF. My understanding from other articles on this, and maybe check out Vibrams on facebook and ask the question there too, is that you pretty much have to harden up the soles of your feet so they aren't as sensitive.
I run with regular shoes, but wear Injini toe socks all the time.
adult running life commenced: March 2009
2012 Rock n Roll USA Marathon 5:28:53 unseasonably hot day, full sunshine, sunburned and dehydrated during race
Omaha Maraton 5:17: __ yeah, new PR! Too bad the brain got in the way and slowed me down! ---recycled glass finisher medals.
April Fools 5K 32:13.7 age division: 28/71
7th half: Kansas City Hospital Hill 1/2--this thing is tough, but the heat/humidity were tougher: 2:45:43
8th half: Park 2 Park 1/2-New PR 2:21 and change
St. Louis FULL Marathon (my first!!!) Hilly, hilly, course full of turns 5:24