I love games with old music in them.
My recent jaunts through the wastelands of Fallout 3 have been nicely accompanied by an accessory radio they give you with your Pipboy3000. The radio plays all sorts of older tunes, and even though the game is set in the future I enjoy the mellow 50's style of music. I love how the game seems to tap a culture that is purely Cold War but is frozen in a post-nuclear age.
Bioshock was also one of those games that had great music. The game also had culturally significant tunes of the a half decade's past (most notably "Beyond the Sea" by Bobby Darin) while subsiding in an futuristic underwater human colony.
Both games seem to stir a style of futurism stuffed in a 50/60's getup. The craft and attention to make something so new yet so old is incredibly appealing to me. I love the idea of a game being one part steampunk, one part cold-war, and one part dystopia. It's an amazing feeling when played, boiling down to two really well crafted games.
And the music is just the icing on the cake.
I'll be downloading these songs on iTunes, because now more than ever I want to walk around modern society with some 50's music on the dial.
Kart-Man
I'm more of a 60s guy myself, but I have to agree, oldies are a good refresher from the standard music you hear nowadays.
Does this mean that you'll take a page from this and end up putting "Blowin' in the Wind" in the next Ball Revamped? :P