I prefer things simple. What I mean is a clean and (for me) simple structure with easy to find modules in the index and other php files plus a nicely ordered css. If the accompanying source files are in png's (I love fireworks) and easy to edit, I'm your man.
"Nice have's?" You know what's nice to have? That things keep working when you are adding one component or module after the other and there are no mootools or javascripts at war with each other, Thats nice

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In a demo I always look for: the main structure of the site, how easily can I modify, the typography, module positions and variations. Everything else is extra.
Just some thoughts, more are welcome, just shoot

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