40K/30K: Let's read!

Hey folks! NoName1 here with another "short" article. This time, let's talk books!

There's an itch for us 40K gamers that the games and Codices and rulebooks, try as they might, just can't scratch. Each of them offers these tantalizing, tiny glimpses and the enormously rich universe that is Warhammer 40K. In our battles, we can Forge the Narrative all up and down that table, but at the end of the day, they're just small skirmishes in the grand scheme of things.

Enter the Horus Heresy book series, and beyond. Here we can dive deep into pages pages (oh god the pages...) of story after story focusing on our most beloved, and most hated, characters. We can watch the fall of Horus from his right hand, we can see a Space Marine invasion from the eyes of a lowly civilian, who may only have the most basic knowledge of what a Space Marine even is. We can hear the stories of how the villains we love to hate became what they are.

I'm nowhere near the end of the series, and I've skipped books (many of which I mean to get back to). But here's my personal truncated reading list from as far as I've gotten.

Books to read:

(The first four HH books set up all the following ones, and add a great deal to later books - even if they're not, themselves, great)
1. Horus Rising
2. False Gods
3. Galaxy in Flames
4. Flight of the Eisenstein

(These were my favorites of the others I've read)
10. Tales of Heresy
13. Nemesis
14. First Heretic (absolute favorite!)
20. The Primarchs
21. Fear to Tread

For a full list of the series, check out the ever-lovely Wikipedia. Note that my own course through the series has been somewhat rambling, based on when I had time to read and which books I had on-hand. However, I have read more than the list above, leading to the list below:

Books NOT to read:

8. Battle for the Abyss (total waste of time, sadly)
11. Fallen Angels

Books that, I personally, thought were kind of...  Meh.

9. Mechanicum (I didn't find it terribly well written, and I hated the loose-end-filled ending)
12. A Thousand Sons (ONLY because Magnus and Ahriman are total pushovers in it)

On my list to read next:
Tales of Heresy
Prospero Burns
The Night Lords series

In addition to the Horus Heresy, I also quite liked Nick Kyme's Salamanders trilogy, Aaron-Dembski-Bowden's "The Emperor's Gift" and "Helsreach," as well as most all of the short-story compilations I've chewed through.
...Also, just about anything Arron-Dembski-Bowden touches is - in my humble reader's opinion - pure gold. Amazing writer in any genre!

Disagree? Let's fight about it! Which books did you love, and which did you feel were a chore to get through?