Most of the sites I work on are biased on the open source project WordPress, examples include Biscuit Mag, Freedom Press, Freedom News, and My Professional site; some sites like Just Vigilantes, and Does UKIP Hate You? are not.
One of the nice things about self hosted wordpress is the backend that allows you to edit and post posts, and pages without knowing any code (WYSIWYG post and page editor)
However sometimes its nice to edit pages off line.
WordPress iOS app
WordPress iPhone App
This allows you to edit of your phone, attache photos and just push them quickly to a site, its what I mainly use to push things to my Project 365.
The mobile app doesn’t give you much control over how things look when published, and for sending media to the site it needs to be online (and now wont send videos to the internet 
).
I use it on my iPhone, however there is also an Android app (link).
Marsedit
MarsEdit Logo
Marsedit is an iTunes download (£27.99) 30 Day Trial. (I don’t remember paying that much for it), I have had it for a long time, and find that sometimes it gives odd code inline, and does odd things with media.
However for some one who just wants to put a lot of content into a wordress blog or site it makes a lot of sense to use this.
PixelPumper
PixelPumper Icon
Pixel Pumper is a new app, its available on the App Store where it is free with an in app purchase (they call this “Nerd mode”).
Like Mars Edit, Pixel pumper does odd things with WordPress Tags and Media (I guess some of the WordPress short codes are hard to understand).
Pixel Pumper also doesn’t seem to render Lists properly 
And wraps things in <div> tags for fun
Oh and what the hell is this error?
WTF Pixel Pump
Like To See
I would like to see an off line WordPress editor that:
- Presented the WYSIWYG more like that in the edit screen for posts (the images and captions being sorted out).
- Categories List could be hierarchical (perhaps drag and drop re-ordering as on Skippy.org.uk the categories have got a little out of hand…)
- Knew about previous Posts and Pages for interlinking
Microsoft Windows
There is still Windows Live Writer.