I have absolutely no problem with huge speakers. I just want the the best sound I can get. By the reviews, it also seems like I wouldn't need a pair of subs. That saves me at least $500 right there.
Keeping you expectations realistic may save $500 too.
How low do your need the speakers to go without subs?
The answer likely depends on the type of music that you listen to. Hip-Hop, Electronic, and Pipe Organs will need the lower frequencies, down into the 20Hz range likely. If you are not listening to these types of music, then you may not need a sub anyway.
Assuming that this is a music system. If this is also gonna play movies, then a sub is typically recommended regardless of the speakers.