It depends on game genre. RPG's, shooters, strategy games should have their on music, which suits the game atmosphere. But racing games, sport games can have normal songs with vocal, etc. Have you played Tony Hawk's Pro Skater series? Music is great there and suits the game well. But for me best "non game" music was in Ed Hunter. The game was an awful shooter similar to Virtua Cop or The House Of The Dead, but there were 20 best Iron Maiden songs. Yeah
