Update: Categories!

From this friendly blog post that gives a very concise tutorial to a very helpful 'label search' feature in Blogger, Google+ user tomgehrke blogs about the feature and shows how to implement this in a step-by-step manner.

At the end of the tutorials Tom even gives 2 tips to help us avoid common pitfalls. It should be straightforward enough for anybody to implement that on their blogs.

Returning from that tutorial, I've implemented labels (or keywords) to almost all my posts. Using those labels as a categorising criteria, I set up a tabbed layout structure to this entire music blog. You should be able to see the tabs bar just below the main title.

In case you need more information, here is another link that shows how to apply labels :)
http://www.bloggersentral.com/2011/02/list-all-posts-of-particular-category.html