"Pmboyd":
For a "budget" 5.1 channel surround sound system, then I would try this approach:
Speaker System Packages:
I would first look at Paradigm and PSB (great sound at affordable prices) and then look at their subwoofers. If not, then I would still look at the Paradigm and PSB Speaker Systems and then mate them with a Subwoofer from either HSU (which by the way, their Ventriloquist line of speakers isn't a bad line to look at either) or SVS. Afterwards, if these aren't exactly your cup of tea, then I would also look at some of the more affordable packages from Definitive Technology. But, I would consider the Def Techs a distant fourth after HSU, Paradigm and PSB.
Receiver:
As for a receiver, then not only I would look at Marantz, but I would also check out Denon, Harman/Kardon and then Yamaha. I wouldn't overlook NAD either.
Good Luck and Happy Shopping........
--Charles--