Not sure what you mean by "heavy", but you might give Vivaldi a try; start with the Four Seasons. It's not minimalist, but it's much lighter than e.g. Beethoven, and not as "serious" as e.g. Bach.
However I find it very difficult not to listen intently to Bach. And I mean that in a good way, but disqualifies his work from being my "working background" music. My pick for programming music is the complete Mozart symphonies. They're also works of genius, but I can be in their presence without my mind being constantly drawn to them and away .
I also go for the Renaissance lute works of John Dowland. In many ways the pop music of the day (and noticeably less sophisticated than the baroque that immediately followed) this somehow puts me in the right mood for UI design.
Perhaps "serious" is the wrong term; maybe "methodical" or "mathematically inclined" is better.