I hate it when WordPress just changes things suddenly*. You log in with your dashboard looking one way and then save a post to have the look and layout of the dashboard change completely.
And it always feels like a step backwards. Oh, I’m sure that eventually I’ll get used to things and it won’t be so annoying, but right now I’m cranky about it. It doesn’t resize well — I frequently don’t have my browser open at maximum width and so now the updated, “floating” right-hand sidebar now overlaps my posting area.
Not happy about that. The new WordPress dashboard design appears to be expecting a minimum window width of just shy of 1000 pixels — I could understand 800, like many WordPress themes, but why 1000? One of the main reasons for locking widths is usually to accomodate header graphics and the like — there are none in the WordPress dashboard so I fail to see why they couldn’t make all of the columns resizeable.
Hrmph!
* (Yes, I know it wasn’t sudden, but I suspect that most people don’t read WordPress.com blog posts.)
Edited to add after Matt’s and my comments below:
Yup, Matt’s suggestions do indeed make it acceptable. So I’m officially uncrankied.
Thanks, Matt! 😀
Life Begins at 41...or maybe 43 
I would recommend two things:
1. Try minimizing the menu by clicking on the arrows in the menu on the left.
2. You can actually make the write page one-colum by dragging publish, tags, and categories into the main column under the post box. (With the size of your screen it may be tricky, but will be worth it.)
Oooh, way to deflate my crankyness, Matt. LOL
The first suggestion is good — I can work with that. And the combination of minimizing the left column and shifting some of the stuff from the right column to the bottom of the center column works out quite well. Consider me completely cranky-free. 😀