Oh yeah, now that I am at my work computer with its giant screen, this new Plurk design is even worse. :|
Simple solution. Do not maximize your browser window. 
That isn't maximized...
Obviously you need a larger background image for your Plurk.
or no background image. (some of us are boring)
It isnt the image that is my issue. It is how much of the window is taken up by the actual field of posts. There is so much wasted space now.