The boss themes from Bayonetta and Darkside Chronicles blew my mind and now I�m looking for more...

Are you looking for specific tracks, or just soundtracks in general?

Specific tracks if you would be so kind.

I'm certain I can think of more over time, but off the top of my head, here's some:

Persona 3 - The Battle for Everyone's Souls (http://www.youtube.com/watch?v=rdMhTL5bZrs&feature=related)
Persona 4 - Mist (http://www.youtube.com/watch?v=IEh3XPic33w)
God of War 2 - Isle of Creation (http://www.youtube.com/watch?v=L09rqYVFxTk)
Shadow of the Colossus - Counterattack (http://www.youtube.com/watch?v=svRZz5t-6uU)
Prince of Persia: The Sands of Time - Attack of the Sand Griffins (http://www.youtube.com/watch?v=-H1GPz2Zg08)
Mirror's Edge - Still Alive (http://www.youtube.com/watch?v=CjsE1JZCSno)
Portal - Still Alive (http://www.youtube.com/watch?v=Y6ljFaKRTrI)
Ratchet and Clank 3 - Courtney Gears Battle (http://www.youtube.com/watch?v=_P3-KiQVDxg)
Sly 3: Band of Thieves - Venice Streets (http://www.youtube.com/watch?v=qee90Gmbj4o)
Phoenix Wright: Trials and Tribulations - The Fragrance of Dark Coffee (http://www.youtube.com/watch?v=bxzTrWUajZg)
Professor Layton and the Unwound Future - Theme of the Unwound Future (http://www.youtube.com/watch?v=sblMhgPlUjU)
Mass Effect - Noveria (http://www.youtube.com/watch?v=wWW-hJbzhSU)

Let me know if you want specific genres of music, or any kind of specific music from games (boss fights only, or forest themes or menu themes stuff like that)

Thanks! Boss themes like the one you posted from SOTC are exactly what I'm looking for.

In that case be sure to check out the rest of the Shadow of the Colossus soundtrack. It's excellent. Here's some more suggestions:

Ratchet and Clank 2 - Swampy Boss (http://www.youtube.com/watch?v=XNGItvTDFGM)
Final Fantasy X - Decisive Battle (http://www.youtube.com/watch?v=NvhFUDWZls8&p=EE9B8E4750CB344A&playnext=1&index=86)
Final Fantasy Tactics - Intersection (http://www.youtube.com/watch?v=rVrQv36YFgg)
Metal Gear Solid - Duel (http://www.youtube.com/watch?v=SSdERzvgUf0)
Metal Gear Solid 2 - Kill Me Now! (http://www.youtube.com/watch?v=GSfDrAy6DVo&feature=related)
Metal Gear Solid 2 - Yell "Dead Cell" (http://www.youtube.com/watch?v=cgxCMMEjpGI)
Dragon Quest VIII - Great Battle In The Vast Sky (http://www.youtube.com/watch?v=_VkVnwfLsiw)
Dragon Quest VIII - Defeat The Enemy (http://www.youtube.com/watch?v=meygA7NcuBg&feature=related)
Final Fantasy VI - The Decisive Battle (http://www.youtube.com/watch?v=BkcODYXxLw4) (Not the original version but I can't find it in good quality since Silvagunner's channel got taken down, but this is the next best thing)
Kingdom Hearts 2 - Darkness of the Unknown (http://www.youtube.com/watch?v=Qz2nEoSYgzc)
Demon's Souls - Maiden Astraea (http://www.youtube.com/watch?v=K-rNVnrFQDg)
Portal - You Can't Escape You Know (http://www.youtube.com/watch?v=5RThhEK2srk)
Valkyria Chronicles - Decisive Battle (http://www.youtube.com/watch?v=_suAWCkeg2Y)
Valkyria Chronicles - Final Battle (http://www.youtube.com/watch?v=ozI4AcYrC08&feature=related)

I can't think of any other boss themes right now. I guess I could post boss themes from Final Fantasy and other RPG's all day, but I'd like some more diversity.

Some great epic battle tracks I can think of right now:

- Awakening ~ Final Fantasy XI
- Esper Battle ~ Final Fantasy XII
- Howl Of The Gathered ~ Crisis Core: FFVII
- Final Gruntilda Battle ~Banjo-Nuts & Bolts (highly recommended!) (http://www.youtube.com/watch?v=w0klqeZIV8Y)
- Mysterious Figure ~ KH Birth by Sleep (http://www.youtube.com/watch?v=fkHefpAki60)
- Bowser Battle ~ Mario Galaxy (http://www.youtube.com/watch?v=53oDNtcSqic)