Hi all. I'm Jin, and I'll be working on the designs for the Stack Exchange sites as they graduate from the beta phase. Each site will have its own unique theme that will reflect its topic. However, all sites will share quite a bit of common elements so they feel like they're part of the Stack Exchange family.
For my research on the design, I've been going through the type of questions asked on the site and your design ideas in the logo post.
I like the Turing Machine and DFA suggestions. I think they represent the concept of TCS very well. For the logo, I normally make its shape to fit within a square dimension; this way it can be easily made into a favicon/apple touch icon.
For the overall design, I believe a clean look would work well, with a few details that have a hint of "computery stuff."
Below is the design for the homepage. While it doesn't have all the site elements, it should give you a good idea of the overall look and feel.
Update: Below is the modified version based on your feedback from the original. I changed the logo to the DFA concept Suresh suggested. I've also updated the question title text from Courier to Palatino. I do think it will look good with the math formula text.
As you can see, for the title header I'm using the Turing Machine concept, and "Σ" as the logo. I'm using a faint water mark of a FSM in the background for pure decorative purpose.
The body section is basically the same as the Beta Sketchy theme structure-wise. The focus here is on readability.
Let me know your thoughts. I'm aiming to get the site launched early this week. So early congrats from me!
P.S. I need ideas for site's 404/captcha/error page images. Feel free to post or link any images you think that'd be appropriate.