I can understand the difficulty of diving into such a deep universe, I was gradually introduced to the lore by playing the tabletop game. But, I do have a few suggestions for you:
-The Horus Heresy novels. These are among my favourite of the Black Library 40k novels, mainly because it gave me a much better insight into how the Space Marines and the many chapters worked. The first couple of novels mainly detail the events leading up to and including Istvaan, and the split between the loyalist and traitorous marines. Not only that but there are plenty of moments describing how the marines live outside of battle, how they interact with each other and of course how they fight. The novels then start to become more chapter specific later on, focussing on how the chapters work and behave differently and in some cases (like the Dark Angels book, can't remember the name) give you the history on how the chapter was formed.
-Other Black Library novels are good too. If there are any chapters that you are specifically wanting to know more about there is probably a novel, or a series of novels, following characters that are part of that chapter. If you are specifically wanting to read about the Ultramarines, there are a series of novels that follow them.
-The Space Marine codex from Games Workshop, BUT only if you have an interest in being involved with the tabletop side of the game, those books are expensive if you are only after lore. It gives you decent chunk of history and information on the Space Marines, and some background descriptions of each of the units. It also contains some cool stuff like a map of space, detailing you where major strongholds are and where engagements have happened/are happening, and some background of some famous characters within the different chapters of the Space Marines.
Since you asked for books I won't suggest any wiki-type sites, but they are handy for checking facts and give more detailed information on anything that piques your interest.
" slightly miffed and dissapointed its going to be a "random draw" figners crossed being one of the first "21st" counts for somthing :( "
It's only fair to make it a random draw. "
not when you think about it objectivly..... but i gues we are both biased in opposite directions...but i will say this.... if you ran a race and came first would you be happy if the gold was given out by random draw between every one that finished the race? "
It had been said that it was a random draw, and nothing said it was a race. Don't really see a problem here.