Fighting games: mainly BlazBlue/Guilty Gear. Love the music obviously, and also adore BlazBlue's overall presentation (graphics, artwork, characters, and how it all comes together, even the menu design). But I have neither the time nor the inclination to study the game mechanics. Speaking as a jump kick/sweep repeat ad nauseam style player of the old Street Fighter II games.
Akira Yamaoka's Silent Hill games: I'm a big fan of Yamaoka's music and a big fan of listening to game music in context. However, I do to horror games what I do to horror movies: turn the volume down. Without the (loud) soundtrack, any horror media no longer scares. Granted, very few top tier horror movies can still utilise minimalism to inspire scares.
Beatmania: Overall, I quite like the various styles of bite-size music here, but again, I have neither the time/inclination to master the Beatmania controller (which I admittedly do have, gathering dust). Besides, I'd rather learn a proper instrument. Which I am.
MMORPGs: In particular FFXI and FFXIV, Immersing myself in the FF world with FF lore sounds tempting. But at the end of the day, most of my time will be spent grinding.
Culdcept series: Culdcept is basically a combination of RPG, Card Battles and Monopoly with music mostly by Kenji Ito. It is potentially addictive but the CPU basically cheats (making you land on their "property" so you are forced to pay them "rent", while they skip over your own "property"). So with knowledge that the CPU uses "loaded dice", it sometimes saps my willpower to play.