One of The 7 Essential Questions of Every Beta.
This one is pretty straightforward. Solicit contributions, throw out ideas, post preliminary (or finished) designs, and be supportive and respectful of other people’s ideas and creativity.
We have designers on staff to come up with site designs but, if an idea stemming from the community stands out as exceptional, we are happy to use it.
One suggestion per answer please, for voting purposes.
Logo guidance, from Jin (resident UI designer for at least some of the Stack Exchange sites):
Please note: I prefer gray-scaled logo submissions, that way we can judge the IDEA of the logo more objectively. We can always add colors to the logo later. Also, the logo itself(sans the site title text) should be able to fit in a square dimension nicely. This way we can use it for favicons, mobile touch icons etc.
UPDATE: Further discussion over on this Question by @Jin - go and have a look, we still need to decide on images for the 404, Captcha and Error pages