What OS?

Personally I think different OS and hardware wins depending on the situation (I have experience mostly of Microsoft Windows, AmigaOS (most people talked about Workbench in the classic arena even though it was named AmigaOS as a whole), and MacOS X (the kernel that was the start up from the beginning was Darwin and is of course open source), but also some Linux (Red Hat and Ubuntu mostly). I hope you will come to your own personal decision what's best for your personality and demands (and hopefully get knowledge about all possible alternatives before).

If you want you can have a laptop or desktop with dual boot (with several OS) as well...works fine on Apple (also with the slimmed, efficient and creative MorphOS - or if you prefer the genuin AmigaOS 4.1 - at the same time), PC, Amiga (for instance Apple with both AmigaOS and MorphOS as dual boot directly on the boot up screen ;) and other computers that you wish to get in motion.