Best Application for updating Social Media?

I want an application to update all my Social Media accounts at the same time, and from the same place.
Ie, Facebook, Twitter, Linkedin (and maybe Blogspot, but I'm not certain that fits the category "Social media").

I have looked around but couldn't find any "THIS is it"-apps.

What do you good people think?

I am looking both for Mac OS X and iOS. (Updater seems to be the best one for iOS, but I'm not sure)

Thanks,
/andreas

Thanks, I'll take a look into these two!