The Chrono Trigger and FFvi main theme's

It's my favorite because of how suprised/strongly I was affected by its beauty. The music in FF II where they are dancing in a waltz on the airship, twirling about. It was so unexpected to hear music like that coming from a video game.

Quite a few, actually. Here are my favorites:

Axelay - (Unkai) First Stage
Axelay - (Mother) Third Stage
Dodonpachi Dai-Ou-Jou - East Asia (Stage 1)
Dodonpachi Dai-Ou-Jou - Colorful Rainbow (Stage 2)
Espgaluda - A Bloody Parting~Mantle Of Blood (Stage 1)
Espgaluda - Valley - Stage 2
Espgaluda - Hige Battle Eriniesu - Stage 3
Mushihimesama - Shinju Heading To The Forest - Stage 1
Mushihimesama - Furthermore, The Desert Must Also Be Crossed - Stage 2
Pink Sweets - Sorelle Forti - Stage 2
Pink Sweets - Svolta! - Stage 4
Pink Sweets - Sorelle Forti (Europop Mix)
TriZeal - Stage 1
TriZeal - Stage 3
God Of War II - The Ascension Of Atlas
Lumines - Shining
Meteos - Florias
Psyvariar 2: The Will To Fabricate - Stage 1
Chaos Field - Stage 1
Chaos Field - Stage 3
Steel Reign - Stage 1

Final Fantasy XII - Main Theme 

Some cool music you all got there. Video game music is under appreciated imo.

Anything from Starcraft/Warcraft.
Zelda theme
Halo theme

warcraft 2 music
God of war 1/2 music
Golden sun 1/2 music

Pokemon Gold/Silver during last Elite Four Battle, SSBM opening theme, and SSBB opening theme

Lonely Rolling Star. - Katamari
Metal Man Stage - Mega Man 2
Sunny Day - Vib Ribbon
Xpander - Wipeout 3

Sonic The Hedgehog 1-3 (and Knuckles). I love the Genesis Sonics! :D

FFVI

Terra's theme...

FFVII

Aeris' theme

FFVIII

Liberi Fatali

FFX

To Zanarkahnd

MGS2

Main Theme

SSBM

Beginning theme