I almost always favor in order:

1. maintenance and readability
2. flexibility, generalization and reuse (if you have to do something twice, you'll need to do it 1000 times).
3. space
4. CPU cycles

99% of the time the last two don't matter. Item 1 matters 99% of the time. Too much focus on generalization will cause you to either write a Turing complete language or never finish your project. Generally, some generality is good (heh).

Readable, well organized code is much easier to tighten up speed or space than overly tweaked "great idea" and "nifty hack" laden code.