DISQUS

To be completely honest, I am bored by the fact that everyone wants to keep Tumblr minimalistic. When i first started using Tumblr, I expected to use it just for sharing links. But proved to be much easier to use than all the other blog platforms I have use. Right now, I use Tumblr as a tumble-log cum blog. I mean it does everything for me that Blogger or wordpress (which makes everything feel too complicated for me) does (except tags,sitemaps,multiple posts and better google indexing).I do however agree that its not for professional blogging. Commenting helps interaction with other users so much easier. If you want to keep your tumble-log neat, just don't show the comment link on the from page. If you are however planning on adding comments to tumblr, I would recommend Disqus (since they have an easy installation method for tumblr). On a side note, what exactly was Current Wisdom (right now it's a blog) ?

@Allan: as a web designer, I recommend getting rid of the automated music on The Natural Life.

This is off-topic from your post above. But anyways I was reading your tumble-log, I came across the piece where you spoke about Litjit. I have tried Litjit. It does a good job but for searching tumble-logs the fastest and best way to find things (without even indexing your pages is using the Tumblr API-powered search. Its pretty easy to set up and the results are instant. You can find a tutorial to install it here:http://www.ziked.com/post/5326924.
Also you should consider adding commenting to your tumble-log - makes it a lot easier to interact with other users.