Most of my music listening now is done with headphones while reading. I don't want to hear vocals (too distracting) or anything too intense or dynamic. Ambient music, at its best, works as background music but can also reward more careful listening. Roach does this better than anyone I've heard (although admittedly I haven't listened to all that many others).
I first discovered his work after seeing a review comparing Monolake's Gobi EP (which I like a lot) to his Slow Heat. From there I kept exploring and now have 12 or 15 of his releases.
YouTube has a short PBS video called The Soundscapes of Steve Roach, which gives some insight into his work.