Paradigm Studio- 40s, 60s, or 100s

I have a room that is approximately 18x14, these will be powered with a Parasound 2205(200x5). I will be using a CC-570 down the road for the center. My main concern is the spacing, I will only have about 7' where these speakers will be straddling a Pioneer Elite 50" plasma. I really want the 100s but I think the 40s or 60s will be a better fit for my current set-up. I have a sunfire sub for LFE....
Thanks,
Jason