I like the Stack Overflow format and I've seen it in other places such as the Codecademy forum. It seems to work well, and it's nice and simple.

I agree with you a lot Jeff, you can't really avoid Markdown. Although I'm hesitant to agree that it needs standardization. You say it's a humane markup language, well if it's meant to be human-friendly then that doesn't exactly lend itself to standardization. Different people have different preferences. I'm no expert by any means, but that's just my initial reaction. For any beginners reading this, you might want to check out my introduction to Markdown that I wrote on my blog: http://codeconquest.com/learn-markdown-youll-thank-yourself-later/