I've got two different versions for testing, one on my main page, the others on my subpages...so far the subpages don't seem to be doing too well. Could you review? As well, I've got a link unit, an adsense in the side bar, and on the subpages, I've got another rectangle at the bottom. main page: http://www.urbanmonk.net/ subpage example: http://www.urbanmonk.net/56/little-secrets-of-the-power-of-expressing-gratitude-even-for-the-bad/
For your adsense ad unit, I would use less ad units and place it in your upper content area (where it is right now : it can get missed easily). Good idea on the 250 x 250 ad placement.
The link unit seems apart from your pages. Maybe it would be better if you place it below your header.
I'll place the Ad Block in the start of the post instead of Middle of the Post, this will help for CTR, rest all things are fine