What Blog Engine Is Best?

I have a running Rails Application and now I want to append a blog to
it.

I've been researching on the matter and decided to try three engines
that I thought were the most popular: Typo, Simple Log and Comatose,
but with each of them I find problems trying to install them: Typo
seems to have a dependency on the SQLite3 gem, Simple log isn't a
plugin you can "plug" to your app, but an independent application by
itself and Comatose seems to have some problems with Rails 2.

I was wondering wich blog engine is the most popular in the group, one
that's easy to install and works as a plug in.

Mephisto works for me - http://mephistoblog.com/

Thanks Pratik. Looks good!

I've tried typo and mephisto. Mephisto lacked some features and was
too inactive for my liking. Typo has a few problems I don't like, but
overall I prefer it over mephisto.