I'm hardly an authority, but I have been attempting to learn to program computers since the fourth grade (I'm over 30 now). It seems to me that beautiful code is that which is powerful and vice versa. Ugly code is illegible, difficult to maintain, and therefore prone to error. Pretty code (in terms of consistent formatting, consistent algorithms, and efficient structure) is usually quite legible, easier to maintain, and less prone to error.

Whenever I feel like I'm hacking away at a problem instead of hacking a solution, I try to remember the three virtues. Will this code be reusable and maintainable, is it efficient, and is it just plain cool? I think a lot of the "software sucks" mentality would go away if more of us worked at these things. Programming is habit forming, and I'd rather have good habits than bad.