tedster - 4:31 am on Oct 11, 2010 (gmt 0)
"Share" seems like a better fit to me, especially since you describe your site as "chatty". The Share button comments look better to me and they are displayed in a more convincing manner. That doesn't mean you can always assume more referrals - but in several cases I'm involved with, that does seem to be the case. A Like button generates a lot less prominent message on your Wall than the Share button.
When the Like button was first introduced, Danny Sullivan blogges about it with some good screen captures - this might help inform your decision: [daggle.com...]