I've been trying to hold this off forever, but... I have to vote for Megaman X.
I just thought it was so damn perfect... it caught the difficulty and
feel of the originals, and kicked it up in a way that Megaman IX (and, of course, MM64) failed so miserably at. (Enter maelstrom of fanboy wrath)
X's music really defined that for me. It was everything that Megaman
was, only perfectly next-gen.
The SiniLegion wants YOU!Signature mostly fixed by Luke. ;)