I see a "The 230 Most Notable Amiga Games" thread coming.
I vote (surprise
) for the Starflight series.
Starflight II: http://hol.abime.net/2107/screenshot
The two original games were PC games and as I understand moderately popular in their own right, but the Amiga conversions (each of which was released about 2 to 3 years after the original) were vastly superior in visuals and game play (mouse+keyboard vs. keyboard only being the main cause), while still being faithful to the original.
I'm fully aware that, while they are my favorites, they're not the
most notable, but I'm sure others will mention plenty of those, so meh.