What do I really need to play Rogue Trader?

2 Players, one Game Master, the rulebook, different dice, miniatures, paper and pencils, sure. But what books/WD articles do I need to have a satisfying game (in your opinion)?

Here's what I have so far:
this red compendium book
the Realm of Chaos books
'Ere we go

Are there really any more books necessary? What about Chapter Aproved? Are the vehicle rules a nice addition to the game in your opinion or were they over the top and not adding to the game in the sightest?

Thanks for your help guys.