I don't have any personal experience with these speakers yet (soon!), so take this with a grain of salt. I've done a lot of research the past few weeks though, so I can share some of what I've learned.
From what I have read on these forums the 350v3 is an awesome sub for it's price. I would go with that if it's in your price range. If you find it lacking you can always return it for a 500, or grab a second 350 to even it out. Your room is about the same size as mine, although oriented a bit differently. I'm going with two 350v3s.
I'd also take the VP150 over the 100 if you can afford it. The price difference isn't nearly as significant as a 350 sub vs 500 or 600. From what I have read there's a bit of a difference. Of all of Axiom's speakers it seems the centers get the most flak, although most of these guys will tell you it's completely unfounded.
As for your friend's system...with a decent receiver you can adjust the center channel to bump up the dialog, that's not really a sign of the quality of the center so much as the setup & calibration. I looked at those Yamahas but decided to go with a Denon 3808 because, like sirquack says, it had all the bells and whistles I was after, and it seems to be a popular choice for Axioms. You can pick it up for about $1000 if you call J&R.
