It can incite or re-awaken all kinds of memories.
I only have to hear a few notes from Nobuo Uematsu's 'Aerith's Theme' and I'm transformed to that 14 year old girl who cried when Aerith died in Final Fantasy VII.
Although the theme music for the chocobos has quite the opposite effect on me, a few chords and I hum it over and over for hours, irritating everyone who happens to be in a 5 metre radius of my dulcet tones.
I've always believed that music is of equal importance to graphics and artwork that make up a successful video game. Even classic games, like Tetris - it's music is based an old Russian folk song- yet we all know it and with it the panic it ignites as the tempo builds!
Similarly, games like Left 4 Dead use musical notes which you come to associate with various special infected; there is nothing more terrifying than hearing the 'Tank' music kick in to get your heart racing or your vocal chords suddenly eminating high pitched squarks, which is my way of alerting the other players - often multiplayer games can be made scarier by players screaming down their mics and causing chaos.
Music complements gameplay in many ways.
It can add to the overall mood or be integrated into the gameplay - for example, Link's Ocarina or the choice to join the Bard's College in Skyrim. Then there's the myriad of games that incorporate plastic peripherals in the shape of instruments. Click, clack, clickedy, clack... Guitar Hero, Rock Band, DJ Hero, Singstar etc. These games sky-rocketed in popularity because of their appeal to a wider range of audience. Before the Guitar Hero franchise and later, Rock Band, would-be rock stars with no real musical talent had only the humble air guitar, but gone are those tiresome days, now you can make actual sound. Or you can learn how to play the guitar, keyboard or drums for real in Rock Band 3, given you have the inclination, dedication and additional funds.
Game music has been so successful that it's even spawned live concerts, 8-bit bands and those musically inspired by video games.
There are many bands that cite video games as reference, use sounds and music from games or integrate video game controllers into musical instruments.
Some like the band Minibosses record covers of well-loved video game themes whilst others create original music using aspects of the game or its sound effects. For example the pop/rock band, I Fight Dragons use Gameboy and NES sounds to create the electronic parts of their music. There's also the lead guitarist in the Brazilian band Megadriver who plays a guitar made from an original Mega Drive (that's the Sega Genesis to all you 'mericans).
Another band that utilises video game music is Horse the Band who once described their music genre as 'nintendocore', one of their songs is called "Birdo" and it's about, well... Birdo (from Super Mario Bros. 2) although it was actually about one of the band's members dislike of eggs! I saw them play here in the UK once and the vocalist dedicated the song to Cadbury's Creme Eggs because he found their concept so bizarre.
Then there's fictional bands like the one in Left 4 Dead 2, Midnight Riders.
Their music was written and performed by one of Valve's composers, Mike Morasky and the trailer for the game featured a track by Clutch. I'd only ever been aware of them by name before the game but it opened me up to their music and I'd say I'm definitely a fan now. Usually, discovering a band, musician or composer is something that happens to me after I've seen a film and have enjoyed the score enough to look it up or make a mental note of their name in the end credits. It goes to show the effect of music in video games.
All of my favourite games have memorable and iconic scores, they might not seem like that to everyone but the same can be said of musical taste or art preference - it's all subjective.
My absolute favourite score is the soundtrack to FFVII by the amazing Nobuo Uematsu. Ranging from the beautiful 'Aerith's Theme' to the powerful 'One-Winged Angel', the exhilarating battle 'Fanfare' and of course, the wonderfully jaunty chocobo music, even better when you hear it sung by a cockatiel...
The music works perfectly and there are few tracks, if any that I dislike and it spans a number of genres ranging from rock and techno to haunting orchestral strings and choral music. Uematsu-san was also a member of the band The Black Mages. It consisted of Nobuo and other Square Enix composers playing music from various Final Fantasy games.
Of course, the theme music of the Zelda franchise is another one I adore and for a long time was my ring tone.
Perhaps it's plain nostalgia but this theme always makes me smile, it captures the adventure and heroic nature of the Zelda franchise and for that, it shall forever remain one of my favourite pieces of video game music.
Ocarina of Time is the one that really sticks out, possibly something to do with the title being musical perhaps? But while it may be the best opening to a Zelda title, the original NES version is my favourite.
Halo... an important game for me as it was one of the first Xbox titles I played. In all it's variations, Martin McDonnell's score in the Halo-verse is sublime. Every time I hear the choir in the 'Opening Suite' in it's various incarnations throughout the games, my pulse races and I'm imbued with nostalgic glee.
I've barely scratched the surface of video game music, there are so many other great soundtracks and musical scores that I know I've missed. Next time you play a game, take some time to just listen and appreciate some of the finest accompanying melodies ever committed to notation.