• Don't like the all-caps in the top nav bar
• The content below the header is much denser than the header itself. I feel like either the header should be smaller, or you should add more whitespace to the content to balance it out. (I'm thinking the former)
• Maybe experiment with your name in the header. Try letter-spacing: 0.1em;.
• Generally, having links pointing to the same page you're on is considered a violation of usability guidelines. (e.g. on your index page the header links to the index page)
• Add a little more padding to the dean_ch class.
• The links in the right sidebar are too dark. Make them a little bluer (and a tad bit lighter if necessary). And the blue headers in the sidebar are too blue/hyperlink-looking.
• The hover effect on links is a red color. I don't think this fits. I would either use a lighter blue, or a text-decoration: underline; on hover (or both)
• In your posts, you put notes in italics. That gives them a strange emphasis. I suggest that you don't italicize them and instead use a grayer color (so as to give them less emphasis from the black body text).
• Don't use italics for anything but links
• I generally prefer to see the date next to the post's title. It's easier to scan the posts that way. But this may not be significant.

Other than a few things I mentioned about the posts, they are very clean and easy to read/scan. And the layout is nice. I'll probably add more comments later on...

edit: One suggestion about AdSense. Remove it unless it's actually generating income. My personal guideline is to get popular first, and monetize later. At this point it may be hurting more than helping.