and it has been some of the best comic writing i've been able to experience. Working my way through a volume of books can be daunting at times, but when it's enjoyable, it makes for a good read. What are some of the best series you've been able to sit down and read in one run.

Actually, I just spent all night reading issues 1-27 and the special issues of Planetary, myself. The Black Glove was something I also read in one sitting. Astonishing X-Men 1-12 comes to mind. Something about Cassaday's art that makes things so much more readable, IMO.

I've read the first 3 volumes of Planetary. Still feeling a little mixed about it. Warren Ellis seems to love talking smack about superhero comics, then goes on to write them. The imagination of the storyline is pretty amazing, no doubt, but I'm waiting for it all to gel together. We'll see when volume 4 comes out in softcover.  
Series I can read in one sitting: Gotham Central, Sleeper, Alias, Walking Dead.

Glad to see more people reading it.

Planetary is one of the best comics I ever read.

Planetary is rewarding for long-time comic readers but it doesn't hurt to use one of the many Annotation sites online to enhance the experience. 
 
The series is densely packed with references so if you're looking to revisit the book, consider doing it with an Annotated guide to pick up everything, including bits you may have missed.