Del.icio.us
I was an early adopter on Digg, back in the day, but it is WAY to immature for me now… I can’t stand it.
StumbleUpon is cool, but I think its best for video and photos. That’s what I use it for mostly, but I don’t do that often because I need to quit Safari and run Firefox for the best experience.
So, in the end, Delicious has won out as my prefered method if finding the tidbits hiding on the Internet that I would be interested in.