Judging by the stuff you seemed interested in, like favoring that blitzkrieg style hit and run tactic and the stealth component i would say stick with Raven Guard or check out the White Scars.
P.S. great job starting with the U Omnibus I started the same way, they only get better though haha.

Thank you for this, its gives me a lot to get through to burn time till the games comes up and feeds my inner space marine. Also your avatar is amazing; it got me thinking of drop pods crashing in and many chapters laying siege to my little pony.

@op First thing, change the Avatar you have, :> That ones a bad guy!!

:> Second welcome to the pain that 40k fluff is, just remember they change stuff (overlords Jervis and co) all the damn time and books of the same generation quite often introduce canon conflicts with eachother which ... well you learn to live with it.

As for long range chapters, possibly something not normally mentioned but possibly Iron Hands but any Devastators/Longer Fanged type dudes excel at long range shooty.

The range of what the loyalists have to offer is pretty cool. Green/Black Angels who aspire to wearing cream, e Stealth Ravens, Mad Red Angels, Beer swilling Wolves, Robotic Metalhands, McDonalds coloured fists (with Hamburgler black available) and yeah Blue awesomeness, Speeding Mongols, and ... well prolly some more I can't think of that all have books about them.

Dark Angels recently got a current time period story update in the 2nd Legacy of Caliban book which just came out, great ending... :> Far better than book 1 imho as well and hopefully book 3 gives some more clues on wtf happened to the ourouborous thing in Caliban (or was that retconned? in 5th ed)

As for other chapters and good books to read through most of them, and some not so good books as
well.

Edit, You like hit and run stealth, That's pretty much raven gaurd, :>

I definitely appreciate finding this thread. I've been trying to find a starting point to get into the WH40k books myself. This defnitely points me in a few directions. Think I'll be going for the Ultramarine omnibus, Space Wolves, and World Eaters ones first. Branch out after that if I get hooked in the writing.

There's also some great Short Story Anthologies from BL. They can showcase SM Chapters that do not normally appear in the Novels.

Lexicanum is always a god wiki to get information from.
I use it to lockup what books i will read next.
Or i just simply read the spoilers and get the information there

http://wh40k.lexicanum.com/

I usually just go to the Black Library site, or if it's from a particular series a forum where the hardcore fans of it go.

Sometimes the contributors of a wiki like Lexicanum use a source that is inaccurate or out of date.
Let's just say that when it comes to BL books Amazon tends to get details like release dates wrong.

Perhaps a bit unconventional, but I like 1d4chan for info on Chapters, Craftworlds, Warbands etc. The articles are short and to the point, and rather amusing as well. They're not just information dumps on the chapter, they also get the personality of that chapter across. Something I find Lexicanum and especially 40K wiki don't.

http://1d4chan.org/wiki/First_Founding

You do know that most 40K-ers attitude to that site is start shouting "Burn the Heretic!"

If you really want information on the First Founding Chapters a lot of their history up to the Scouring can be found on The First Expedition.
www.thefirstexpedition.com
http://z13.invisionfree.com/The_First_Expedition/index.php?

There may be gaps in their knowledge, okay our knowledge, but that's because we haven't gotten it out of Black Library or Forge World yet!

If you enjoyed the Dark Angels try the Soul Drinker series.

Its one of my all time favs.

And you honestly should really give the Space Wolf Omnibus another shot.

The adventures of Ragnar and friends are great.

But if you just want typical Space Marine bluster and holding the line against unbeatable odds read "The Battle of the Fang". Its another Space Wolf story but it has some of the best characters in 40K I've ever read about and it has great characterization of my favorite traitor(debatable) legion! The Thousand Suns and their Primarch Magnus the Red.