I generally think that the default admin area is okay. However, a little tightening here and there can’t hurt: this is where BinaryMoon‘s BM Admin Tweaks plugin comes. This plugin minimizes many part of the admin (typefaces, padding, to mention some), saving many precious vertical spaces so that you can get more things displayed at once on your screen. Try to compare the default write post area with and without this plugin, for example. The difference should be pretty clear. That’s not everything of course: most of the tweaks are pretty small, but you’ll see that the admin area suddenly becomes more focused, with better usability, and more pleasing to the eyes.
Verdict: it’s awesome. I’m using it.