For those of you that are using Firefox and would like to have these remixes as MP3s, then this little gizmo might be of use to you.
Hikarisy: Snake Man
My favourite stage music from Megaman 3 gets a rockin' heavy metal version, and it suits it perfectly. Hikarisy has a few other Megaman remixes on Youtube, and they're all pretty fantastic.
Onocchi: Armored Armadillo
Armored Armadillo has the best music in the whole of the Megaman X series, which is high praise indeed when you consider how good the first three MMX soundtracks are (and the rest are good too, just not as good). Another high-energy metal remix, it starts off as an excellent version of one of the more difficult MM songs to play, but then at around the 0:58 mark, more guitars are added and the whole thing goes into some kind of blissful super-rock overdrive. There's a link in the YouTube description that'll take you to Onocchi's site, where you should download all his videogame remixes because they're fantastic.
Chiptuned Rockman - Kaze Yo Tsutaete (Buster Core Meltdown mix)
It's Roll's Theme, originally from Megaman Battle and Chase and also heard in Marvel vs Capcom and Tatsunoko vs Capcom. However, it has been recreated in glorious 8-bit NES sound, and the end result (like pretty much every track on the Chiptuned Rockman album) is truly glorious. Check out the bit at 2:24 where she says "Megaman!" in her little chiptune voice: it is sound to warm even the coldest of hearts.
The Megas - Annihilation of Monsteropolis (Airman)
? - Gravity Man
Dangerous Mezashi Cat - Megaman 3 Title Rock Remix
McVaffe - Cutman Sonata
Alph Lyla - Scrapping Beat (Flame Mammoth)
Daveeeey - Plug Man with MMX2 Instruments
The title says it all, really. Plug Man's theme from Megaman 9, recreated using sound samples taken directly from Megaman X2. A simple idea, but one that works brilliantly and will have you longing for a new SNES-style Megaman X game instead of the rubbish recent ones. Also check out his versions of Castlevania tracks using the same idea, which I think might be even better than the Megaman ones.
? - Skull Man Guitar Arrange
And finally, one of my very favourites. This captures the essence of Skull Man's music perfectly, with the added bonus of rocking harder than a concrete rocking-horse. Short, sweet and to the point, it'll make you wish Capcom would release the older Megamans with this type of music.
And that's it for now. That lot should give you something to listen to, eh? I'm always open to people suggesting Megaman (or any game, really) remixes for me to listen to, so if you know of something you think I'd like, let me know in the comments!