There are two categories of newsletters: the ones you don't want to hear about a week after the first issue and the ones you look forward to seeing in your mailbox. If you are interested in launching your own, then you are probably more interested in the second category. Here are four very different kinds of newsletters that continuously deliver real value to their subscribers.

Brain Pickings Weekly: the hyper creative full-time job newsletter

The Brain Pickings weekly Newsletter is an open window to the world. It presents a handful of chosen works - mostly books - selected based on their originality. Maria Popova, a young New-York based Bulgarian writer, reads tons of books and introduces the ones she liked the most in a very personal and creative way. Recent reviews include a piece on the philosopher Alan Watts and his works, the forces behind motivation and a guide to a happy life. This newsletter is one of the best on the market, bringing together a beautiful design and a highly original content.

Long Reads Weekly: the high quality community managed newsletter

 Frustrated with blog posts you are done reading within minutes? Long Reads is for you. Started in 2009, it offers a wide variety of thorough articles and blog posts (usually 5 a week) on any topics. It's ambition: "sharing the best storytelling in the world, including both nonfiction and fiction". Another feature distinguishing the selected articles is quality. Most of what I have read was very well-written and highly captivating.

James Altucher: the newsletter as an exclusive post

James Altucher (from the Altucher Confidential blog) is either a screw-up or a genius. Whatever he is, one can't deny that he is really good at staging his own mistakes and sharing what he learnt from them. James started several businesses and almost none of them survived. Constantly bouncing back, James knows a lot about winning but also, and perhaps most importantly, he knows what losing everything means. Each newsletter has the same format as the blog post, except that it is not published on the website. Covering entrepreneurship and other aspects of life, you will find several types of posts.
The list post
"33 tips for being a better writer" (which is excellent)
"10 alternative choices to college"
The "That happened to James" post
How I did/was/suffered from [something terrible] and got away with it
The Cheat Sheet post
The Ultimate Cheat Sheet For Investing All of Your Money
The Ultimate Guide for Becoming an Idea Machine  

Hacker Newsletter by Kale Davis: the newsletter as a digest

Ever found yourself spending more time than you should on Hacker News? This weekly newsletter gets you the best content seen on the infamous news aggregator. Conveniently sorted by categories (favorites, code, Show HN, Ask HN, design, etc.) it brings you everything that drew the eclectic Hacker News community's attention. What makes it so great is that the selection is based on the votes of the awesome Hacker News community (entrepreneurs, developers, students, ...).

Your newsletter

Whatever the topic of your newsletter might be, you absolutely need to know what value you are offering to your subscribers. Ask yourself relentlessly these two questions:

1. Among a hundred newsletters, why would someone pick mine?

2. After the hundredth issue, why would someone look forward to the 101th?

Originality and quality are two powerful yardsticks that can help you estimate the future success of your newsletter, always keep that in mind!

Please add any newsletter you find particularly awesome in the comments :-)