My absolute favourite album to code to would actually be the Tron Legacy soundtrack by Daft Punk, but I've also spent the last few years at uni listening to http://www.prettylightsmusic.com/ while I code: his albums are all available for free/donation, and the genre is kind of down-tempo electronic. There's the occaisonal vocal sample, but I've found it doesn't distract me from work. Endtroducing by DJ Shadow is also…
Some of the tracks from the remix album are also pretty cool.