There’s a program called Famitracker that one can make tracks for the Famicom, or the NES in the West, which can be implemented in homebrews or just enjoyed as they are.
Here are some of the more awesome tracks that I’ve found so far:
8-bit Spark Mandrill Stage Theme
The Spark Mandrill theme is my favourite of all the Megaman X music, and this rendition truly makes it justice. Just listen to the original:
Even though the 8-bit version is based on the weaker NES chiptune set I still consider both of the versions to be pretty much on par with each other. Both of them are goose-bump-worthy.
This one is a rendition of the intro stage music in Megaman X-2. Awesome, isn’t it? The whole feel of the original music is well captured, even if the NES “instrumentation” is a bit weaker. In this case this version doesn’t stand out as pompous as the original but it’s not far off at all:
And below we have an 8-bit Bob-Omb Battlefield from Super Mario 64:
And here’s the original: