Sharp, clean sounds with a bit of nostalgia. It appeals to a certain demographic; if it's not for you, then so it goes.

I used to listen to it but then I realized, "holy fuck why am I living in the past?"

Also, if you want sharp clean sounds you can listen to minimalist techno, some house music, etc. Most music is composed of sharp clean sounds because it's digitally recorded and fine-tuned by sold sound engineers.

Like with anything, creativity can spawn some really good 8-bit music that isn't only re-hashed zelda tunes. For a good starting point, have a look at that documentary I posted in the comments, I used to think it was just "living in the past" until I watched it and looked up some of the music.

edit: I'll include the link again for the lazy: http://www.vimeo.com/3734864

It's often distributed as scores (source code) designed for a particular classic synth chip (an API), not rendered audio. It's very hacker-friendly.