Ok, so, say you're playing NWN multiplayer or any rpg and have to face a uberboss in ultimate difficulty. Some people think that just having the right equipment and level is all that you need.

I DO NOT AGREE

you need an epic battle soundtrack (like the one of the final cutscene on ME2)

http://www.youtube.com/user/DragonstarDT

There are a LOTTA of EPIC MUSIC

Also:
http://www.youtube.com/user/musichealsursoul

Always going back to these channels :) Epic Music gets you through everything.

And that IS A FACT

FACT: Oblivion goes from good to epic when you install the massive free music pack a fellow put together. Makes a fight with an imp sound like a Final Fantasy boss battle.

Well, you can't go wrong with a piece of classical music titled Entry Of The Gladiators, can you?

Hidden Turtle Room fight music in Titans Quest... most epic music ever in the history of everything and all time to succeed and live beyond entropy itself!

Bang Camero - Rock of Mages

I highly doubt any game as more epic rock music to keep you fighting in the hardest fight of all fights!

Just Netflixed that movie.. awesome!

This one, because I know everyone loves it so damned much!

http://www.youtube.com/watch?v=LUjxPj3al5U

I'll have to disagree with you on that one. The vocals are horrible.

That's Ian Gillan from Deep Purple, everyone hates that song.

There is no music more epic and suitable for AWESOME battles than this

http://www.youtube.com/watch?v=onGWF8mz1Zw

I would suggest that one. Final confrontation from Castlevania Lords of Shadows by Oscar Araujo. http://www.youtube.com/watch?v=nmpL8FTwED4&feature=related

Just Awesome. Especially near the end.

All the songs from Two Steps From Hell are amazing. Their music has been used for trailers such as Star Trek (song was Freedom Fighter) or the Mass Effect 2 launch trailer (Heart of Courage).
many songs here

They have released a download-only album, Invicible, which is pretty nice. Not all tracks are as awesome as the two that I mentionned, but most of them are very good.