Here's a couple examples, off the top of my head, of great music from games. Don't know if these have been mentioned but hey:
- Far Cry 3: Blood Dragon soundtrack, specifically the main theme, and power core. And maybe also the love theme. I might be biased because I loved the game, but I thought its music was both effective and memorable.
- Binding of Isaac ost - again no vocals, just really catchy, effective music.
- also - randomly - the main theme from the old Dawn of the Dead. That slow beat really sinks in for me
https://www.youtube.com/watch?v=s4Xw_7BUXic