Are there any other good operating systems besides Windows, Mac, and Linux?

Unix comes to mind.

Haiku has potential (but it is still alpha right now).

Maybe Ubuntu? But don’t take my word for it :P

www.ubuntu.com

Unix inspired Linux but is now obsolete for the most part. Ubuntu is Linux.

There are zillions of other OS’s, but I personally haven’t run into a non-UNIX-based system I’ve liked.

This is an odd question.

Windows is not a monolithic operating system, – there are at least three variants in wide circulation at the moment – XP, Vista and 7. The same is true, to a lesser extent, with Apple’s operating systems. However, MacOS represents closely-related variants of Apple’s proprietary Unix.

“Linux” should not be conflated with “operating system” either – it is a veritable menagerie of operating systems running on everything from supercomputer clusters to cable desktop boxes to phones (Android). Linux is itself a Unix-impersonator (or derivative, depending on your point of view)

Also, by “good operating systems”, for what purpose of the operating system would you base this opinion? Obviously the Android OS would not be very optimal to use on a supercomputer, just as the Cray Linux Environment would be pointless to use on a personal desktop computer.

I once did a lot of programming for a compact OS called vXworks. It’s used primarily on realtime embedded systems. It has some competition from Linux. I’ve heard good things about Chrome, but I haven’t tinkered with it personally.