Let me first promise that this is my last post with the annoying 'd in the title! 
Two days ago I spent about 15 minutes setting up Google Friend Connect on my blog -- I just wish it was more than a bunch of widgets and probably Google is already working on that. The process was simple and pleasant.
Yesterday it took me about the same time to also enable Facebook Connect here using Adam Hupp's plugin called WP-FBConnect, which is the official one for WordPress. The two other plugins seemed either too invasive (Sociable!) or too early in development (Community Facebook Connect by Jessy Stay). There is an official Facebook Connect Plugin Directory now and, which seems to be actively updated.
I had to make a few minor tweaks to WP-FBConnect -- the first and last names of users were not getting populated in the database and the CSS did not match my theme well, but in general it was also simple and pleasant experience.
What I find sad is that Yahoo! has failed to maximize the full potential of their MyBlogLog service -- they've got all building blocks necessary to offer a combination of both Facebook Connect and Google Friend Connect -- identity, widgets, lifestreaming, friends, communities, following. Oh, well... again and again, Yahoo! is letting competitors eat its own pie.
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It’s nice to see this Plugin working, but how is it affecting you visitors. Do they comment more often or are you getting more visitors on the blog?