Is a site critique appropriate for SO? What about a focused subset of a critique (e.g. how can I simply refactor my color scheme?) If not, if y'all have any suggestions for other sites to go to for good website critique, that'd be a nice alternative.
I don't think it's appropriate, because in a lot of cases it's really just someone saying "hey everybody read my blog that you don't care about!"
Now, if there are questions about particular design decisions, you could post screenshots with generic content, along with an explanation and simplified markup, and I think people would be fine with it. Don't make people follow a link to a site they've never heard of that could be spam or a virus or who knows what.
Edit: Maybe saying that it's never appropriate is a bit draconian. I have seen a few cases where it was okay where someone basically says "I'm having this problem on a site and I've tried X and Y and Z and here is the code but I can't seem to reproduce it in a small bit of code--only on the live website. Can anyone take a look? the page is blahblah.com/testpage.html and the problem is with the option boxes halfway down." In other words, they showed that they tried their best to produce a code sample but it didn't work.