I've picked up 3 copies of the base set but with Doomtown and ANR I just haven't had time to really explore it. I played a few demo games and thought the small start decks sucked ass big time. I just haven't had time to explore the cards properly and it is starting to gather dust.

Is there a list somewhere of some decent fun decks that can be built all at once with 3 cores for all or at least most of the factions?

I simply made single-starter decks out of 6 of the factions, so that we can flop around and test all the different cards. Guard/Marine, Marine/Tau, Eldar/Tau, Deldar/Chaos, Chaos/Ork and Ork/Guard are the 6 I built.

Check out Card Game database at http://www.cardgamedb.com/forums/index.php?app=core&module=global&section=register for all of your Conquest deck building needs. It's awesome.