Re: Fixed width for default theme & admin bar?
It’s funny you ask because I’ve been debating this in my head today.
Right now I moved to a static 980px width. This still gives some whitespace on the default theme when viewed on a 1024×768 display. I opted for a fixed width because the flexible width of the main content area wasn’t working for my design plans.
Maybe it’s also just a personal preference, but even on my 1600×1200 main display, I still only allow my browser window to be 1024 width max.
There is a maximum width for any content area before the human brain can’t handle it. There’s a reason newspapers are in columns. 
It’s also interesting to read about the “golden ratio” and how it can be applied to web design.
