The default templates that come with MT 3.0 are almost OK.
I have two pet peeves: first, there is no full posts rss feed; and second, the individual archive template lacks the right navigation bar of the main index template.
I want the first one because it's my preferred feed type. Almost all my feeds that I subscribe in NetNewsWire are full posts.
To solve that, I added a new index template, named rss-full.xml, and changed the default rss 2.0 template to output full posts. The result of my work can be found in the full posts rss template.
The second one is easy to understand: all the RSS/Atom feeds point to the individual archive page, so it makes sense to have the navigation there too.
Frankly, I expect most of my traffic from the archive pages, and not the home-page.
The edited individual archive template for your download pleasure.