Mac OS vs WinOS
Apple actually went to court with Microsoft over this issue years ago. Apple claimed that Windows was an indirect copy of Apple's OS.
Anyway, the judge finally ruled that Microsoft didnt steal the OS from Apple, but Xerox, who was using a 'window' driven GUI (instead of code) for their printing systems, along with a mouse. Apple had actually done a bit of research with Xerox as well, and the judge ruled that BOTH of them really didnt innovate the GUI. Xerox never went to court with either of them.
However, Apple WAS the first DESKTOP computer company to popularize the GUI, and Microsoft just played catch-up for the first couple years. I think that is why Apple reps. claim they came up with it first. They didnt actually 'invent' the GUI, they just made it practical and useful to the masses.
To use an analogy, Xerox 'discovered' fire, so Apple built the fireplace.
SO, no. Microsoft didnt REALLY steal the idea from Apple. Apple visualized desktop/home computing using Xerox's GUI idea, and Microsoft just jumped on the new bandwagon after Apple did. Now, however, if you ever hear people talk, it was Microsoft who innovated this entire thing, when really they were the last ones to do it. Kinda like hearing Al Gore say he invented the internet.......
I still think, however, that Apple always did, and continues to produce the easiest, cleanest, and certainly best-looking OS out there. Now, its a bit more powerful with Unix under the hood, but some hard core programmers would still tell you that their Unix still has a long way to go. I just want OSX to go FASTER.