Activity Feed

I would only
recommend this plugin if you believe there is enough activity going on
at your blog other wise it wont leave a good impression at the visitors.
Comments
Comments
plugin lets users to comment on your blog. A great feature of this
social plugin is that when ever someone comments on your blog and leaves
the "Post to Facebook" check box ticked, the comment appears on his
Facebook activity feed with a link back to your blog and thus making
increasing more links towards your blog.
Also this comment box is extremely user friendly and is quite simple to understand.
You can add it to your blogger blogs by reading this tutorial: Facebook comments Box
Facepile
The
Facepile plugin shows the profile pictures of all the people who have
liked your blog or have signed up for it. You just need to enter your
blog URL and your plugin would be ready to go. This again helps only if
your blog have enough likes and followers.
Like Box

You can add it to your blogger blogs by reading this tutorial: Facebook Like box
Like Button
Like
button works somewhat like the "like box" but have a different purpose
to serve. Its a more handy button and can be added to places like post
headers and footers. Its just allows to like your respective post or
your blog as a whole. Today, Facebook likes have become one of the
determinants of your online success. Its a must to have plugin.
You can add it to your blogger blogs by reading this tutorial: Like plus Send Button
Live Stream
Live
stream plugin lets users to share comments and activity in real time on
your blog. Live Stream works best when you are running a real-time
event, like live streaming video for concerts, speeches, or web chats.
Login Button

Recommendation
This
plugin features all the recommendations your blog has earned. Whether a
particular post or the blog as a whole, the plugin would show that
content as recommended by so and so.
Send Button

You can add it to your blogger blogs by reading this tutorial: Facebook Send Button
Which one to choose?
Facebook
social plugins are really one of the best out there as part of social
tools available online. Its not necessary that you should use all of
them to get online success. Instead work out your needs and then choose
which ones you want. The most famous are Facebook like button / box,
comments.
We would like to know which of these social plugins you use on your blog.
Thanks