I thought there was a ticket for this, but I can't find it. One of the slowest pages on my site is the list of blog entries, which is not cached even though I have all caching options turned on and the content changes on a very rare basis. The only data that might change now and then is the number of comments, but I'd still be willing to cache that screen for hours at a time (or days really since one of my blogs doesn't even have comments enabled).
Enable caching of the blog listing page. Even if it's just on the first page of results, that would be pretty good.
Another good place to cache listings would be when viewing a category like so: