What is the best Tablet for my needs?

[Andrew]

I'm looking for a tablet that will be able to do the following:
-Play media files (music, videos,)
-Be able to browse the web, facebook and twitter.
-Be able to support the celtx app for script writing.
-Will have an external keyboard peripheral available.

I'm leaning towards the ipad as I can do all this stuff with my iphone, but want a bigger screen, the thing is I'm worried the ipad mini might be too small and not have any keyboard peripherals that I will be comfoortable writing on.
I'm open to android tablets as well however, just have no knowledge about it.