Wolfgang Voigt is a worthwhile artist-- though I've only heard a small fraction of his vast output, it's probably safe to say he's Not Crap based on Gas alone. Get the feeling that I wouldn't be nearly as keen on Voigt's overtly "micro-house" fare, though (not a big fan of that style, as opposed to Gas, which is pretty much "ambient music" despite the periodic presence of a 4/4 kick).
Only own
Pop and
Koenigsforst but have enjoyed these records immensely. They're ideal for both active listening and as background music for when you're sick or headachy or trying to clear your mind of extemporaneous thoughts.
Pop in particular is very lush and lulling.
Bleep recently issued
four Gas albums available for download. The track "Pop 4" is my favorite, and probably a good introduction, along with "Koenigsforst 2".