Hello.  Is the RT core book a complete game?  Im interested in purchasing RT but would like to know if the game runs well with only the Core book and say the Gamemasters Kit, or will I have to purchase other books to flesh stuff out to have a good experience with the game? 

Thanks

Gary

The core book has everything you need for a basic delving into the game. That said, there are a great many things that suppliments offer, such as:

Advanced Origin Path and Homeworlds (Into the Storm)

Alternate Career Ranks (Into the Storm, Hostile Acquisitions, Navis Primer)

Xenos PCs (Into the Storm, Soul Reaver)

Vehicle Rules (Into the Storm)

Torpedoes, Nova Cannons, and Attack Craft (Battlefleet Koronus)

Xenos Starships (Battlefleet Koronus, Edge of the Abyss)

At the very least, Into the Storm offers a great deal of extras in a single added book.

The Core book is definitely completely servicable. There aren't really any scenarios where you're going to say "Curses! We can't do this sort of adventure because I don't own the book!" Into The Storm is a solid, all-purpose expansion, and the rest are situational and should probably be Acquired based on your group's preferences. (IE: If your group spends all day in ship combat, Battlefleet Koronus's extra ships and ship types will probably serve you well)

Thanks all.  I was hopeing that the game would stand on its own.  It appears that it will work fine with just the core book + published adventures.  I used to own close to 70 of the World of Darkness books split between Vamp the masqerade, Werewolf the apocolypse, and Mage the acension, but i only used 9 of the books, and we played a lot, for years.   So im trying to avoid buying a bunch of stuff that I will never use or only uses rarely.

After researching some of the books that you all recomended I have to say that Rogue Trader: Into the Storm, and Rogue Trader: Battlefleet Koronus sound very good!

Thanks for all of the advice on viable expansion books.  Its nice to have a roadmap for the future in case i decide that I need more stuff.  

Thanks again

Gary

Into the Storm and Battlefleet Koronus are very good choices for extra books. There's one more I'd really recommend though, at least if there's an astropath or navigator in your group. The Navis Primer features a lot more detail for those two classes. In particular, the book expands a lot upon two concepts that I felt were sorely lacking in the core book. These are warp travel and warp communication. Both are covered in-depth in The Navis Primer and will be something your group will use every time you try to travel between stars or send an astropathic message. Among other things it will tell you, in rough terms, the travel times between specific systems in the Koronus Expanse and what challenges these warp routes present. All of this was annoyingly vague until this book was released. There's more to it too, but those two are the main reasons I like it. 

One thing I enjoy with the FFG 40k games, is most of the supplemental books are good, sometimes TOO good, to where you NEED them because they add so much.