Worried about the Aqua interface for OS X? There is at least one replacement theme available, Bruno Blondeauis NextAppearance. NextAppearance gives Mac OS X Beta the look and feel of the original NeXT OS. More significantly, it eliminates the system-wide antialiasing, and demonstrates that there are at least some interface options for the forthcoming OS. According to Mr. Blondeau:
Tired of the Aqua theme? Try NextAppearance and all your Cocoa applications (such as Mail.app or the System Preferences) will automatically sport a new user interface! Caution: due to some bugs in MacOS X, this new theme is not perfect, and some applications freeze when you click in a text field (you have to kill them in this case).
NextAppearance is available for free. You can find more information at Mr. Blondeauis web site.