[bluedays]

You can install any Desktop Environment you want.

[hulitu]

You can do that in any distro. I think the OP refers to the fact that, usually the distro supplies some default config files for the DE which makes it look distro specific.

[zinekeller]

... except that it's command-line by default, so the DEs has whatever Gnome/KDE decided them to look (rather than adding wallpapers and such).