[Kale Hellas]

welcome, to the community.
i suggest you get assault on black reach, it helps a lot.
i live half an hour from melbourne know what you mean by being stared at the games workshops in melbourne with the exception of northland and occationally highpoint arent that good to learn in.

 

[Kale Hellas]

well angry marines aren't exactly an army, they are but not a games workshop one someone made a fandex for them, you can come up with your own space marine chapter.

 

[Kale Hellas]

probably, if you go with any spacemarines i suggest the basic spacemarine codex it covers all the chapters except the very specific ones.
but as grish said check out gw online and find out what army you likethe most.