Turbo Pascal for DOS. Simple, compact, quick, well documented, reasonably easy to learn, and not too expensive. I think that bloat is the enemy of beauty, so we're probably likely to find beauty in software that does a few things well.
- Things That Turbo Pascal is Smaller Than: http://prog21.dadgum.com/116.html
- A Personal History of Compilation Speed, Part 2: http://prog21.dadgum.com/47.html