I think the hardest thing here is that you're looking to buy a system that you're just going to replace in a year (receiver and all).
Personally, I'm a Harman/Kardon man and couldn't resist chiming in because you brought up the AVR7300.
I think you would be better off a this point buying your system in several parts.
Part 1 -- Receiver, Front R/L, Decent DVD Player
H/K AVR7300 -- $1342 @ OneCall.com
Infinity Primus 150BK -- $199 (Pair)
Oppo Digital OPDV971H -- $199
Total: $1740
This is your starting point. You'll have the receiver that'll last you through the entire upgrade, and a decent DVD player that'll use DVI to your new plasma TV.
Part 2 -- New Front R/L, Center, Sub
Infinity Primus 250BK -- $400 (Pair)
Infinity Primus 25BK -- $179
Infinity PS10 10" 200w -- $349
Toal: $928
With this, the 250BK's would become your Front R/L, and you'd move the 150BK's to bear your Surr R/L.
This would give you a GREAT sounding 5.1 surround system with a receiver that has enough power to last you years.
I agree with jaxvon that you should also invest in some decent shielded cable and a power conditioner (Belkin or Monster).
In the end, I still always say choose the products that sound best to you! Everyone is going to suggest the brand that they own, but it might not always be the best for you.
Go to some stores and listen to demo system.
I still think splitting your purchase into two parts is the best. This way you're not buying equipment you're just going to replace in a year. That's just a waste