[Jennifer]

It's really a matter of taste. For Monkey Island 1, a lot of people prefer the Amiga's music, and a lot of people prefer the DOS VGA CD's music (me included, although these days I play the DOS VGA version with Jesse Harlin's music from the SE). There are multiple versions of the DOS version of Monkey Island as well. The DOS EGA version includes a sunset over the harbor and cartoon style closeups (as well as an additional joke in the Voodoo Lady's shop about Charles Atlas that was removed from later versions due to legal reasons). The DOS VGA CD version (and versions based on that version, such as the Sega CD version) removes the stump joke in the forest. The Sega CD version has some censorship (hell is changed to here in the monkey head).

For Monkey Island 2, the versions are mostly the same except of course for differing amounts of colors and differing audio due to the games running on different hardware. Again, this is a matter of taste (and usually comes from which ever version people played first).

If you want the original version, the DOS versions would be it (EGA floppy for MI1, MI2 only had one DOS version AFAIK). But both Monkey Island and Monkey Island 2 were built with the MT-32 sound device in mind. If you don't have an MT-32, the MT-32 emulator in ScummVM is really good now in the latest daily builds.