Thanks for the replies! To answer some questions:
That x3300 has been on my radar. Looks like a great deal. I was just concerned that 105w would not cut it. I've read elsewhere that 8ohm with 88% efficiency is not very good and would take 140w+. If the audioholics think it is enough, then I'm quite comfortable with that receiver - and at half the price I thought I might have to spend.
I actually didn't even follow the link. I saw what it was and went straight over to the Amazon app, where it is listed for $599. Thanks for the advice about the seller. The default seller was not an approved dealer, but others that were have it at the same price.
The .1 in my system for now is indeed a psw505 from Polk. I've had it for years and it's always sounded alright to my untrained ears in the cheap surround system I was able to afford in college (Energy take classic). My plan is to upgrade to .2 with some nicer matching subs later on.
My budget now isn't really restricted except by reason. I'm sorry that's not very specific, but for some perspective, there's no way I could reasonably drop $2,500 a piece on the 16" SVS subs on Amazon. My conscience wouldn't allow it, and my wife probably wouldn't either. I could however go for the pair of sealed 12" 500w ones for $1,300 if that will suffice for the system/room. I might even be able to squeeze them in now instead of waiting if I only spend $600 on the receiver. I've always wanted a 15"+ sub to really reach those heart-shaking lows, but the high-end ones from good subwoofer brands are just insanely priced in my view. Perhaps my views will evolve with more time.