I've blogged for so many months now that the Archives listing on the side was getting pretty long. I don't really want a long list of months and years there, so I was looking for options.
Ned Batchelder lists his archives by year. For each year, there's a summary page by month which lists the dates and titles of all blog entries for that month. I really liked this idea, so I wrote my own archives plugin to use it. It's not exactly the same--the output is slightly different. It's good enough for me, though.