I really like this list. I think the only opinion I don't share is number 20- "Less code is better than more". I've been coding in C++ for a while now and approaching a problem without an object-oriented focus can yield substantially less code, but it's not very readable nor flexible for quick changes later on. Also, if performance is key, you may want to dig deep and that usually yields a lot more lines.

I started using Ruby this summer and it was fun turning 10 lines of code into 1 or 2. But it was a big pain deciphering it weeks later =(