Evernote + Tumblr Web Client
I tried out a few desktop content creation clients for Tumblr but none came close to the web client. The only desktop client worth mentioning was Windows Live Writer but sadly, it does not support Tumblr.
So, now my plan is to use a combination of Evernote and the Tumblr Web Client. Evernote will allow me to keep the content sync up between my various machine and Tumblr Web Client is accessible from wherever I have an internet connection.
I am testing a few desktop publishing solutions to avoid the whole browser process.
Putting things in perspective!