I have a confession to make: I really like Ubuntu’s design, its look and feel, and its colour scheme. And it seems to get better with each release. The new Natty theme is really beautiful, and the dark window decorations of the Ambiance theme are great (especially now that they’ve chased down the odd dark text on dark background problems).
Having said that, there’s one thing that I really don’t like: the way that it’s virtually impossible to tell what you have selected in windows other than the one that happens to be focused. This is because the focused elements get completely desaturated, like this: