See our existing logo at truestreetcars.com. I'd like to update it. As our community is very broad we never could get a logo that everyone liked so we kept it simple, just a font. It's worked well but I'd like to update it and have something more professional. Here are some links to threads regarding our logo and some ideas for other logos (that were ultimately not used) but it gives you an idea of what we've done and what our audience likes/dislikes:
Our audience is mostly male, 16-40, who enjoy the edgy attitude of the site. We don't censor content and we encourage activities that others might not agree with. Our users can be tacky but intelligent at the same time. Given the broad range of makes/models of cars on the site we can't use a specific model car on the logo. We'd like something edgy and aggressive that doesn't lack some class and still appeals to an older audience while not being completely boring. Ideally it would be a logo that would appeal to any street car enthusiast.
We've attached a couple logos we've used in the past, though we're trying to change them so don't worry about going a completely different direction. A lot of people refer to the site as "TSC" so maybe that can be incorporated somehow. The logo will need to be scalable as it will be used on t-shirts, hats, beer mugs, etc.
Edit, added 2/18/12: After seeing many designs I think we may want to stick with the current font as the base, it's called "Angry Blue" (http://www.dafont.com/angryblue.font). Use red/black/white as the primary colors. Maybe give it some texture, move the dotcom around (above, below, a different font, cut out, etc). An icon/shape along with the text might work, something in addition to the domain name that makes the entire logo recognizable as our logo when the actual text can't be read (on a small sticker for example).