You hit the nail on the head for speakers. Personal preference all the way. Subwoofers are a little more about the specs (output level, bass extension, etc).
You have lots of good considerations, so I'll just throw in some more:
PSB
Rocket (from
AV123)
Axiom
Totem
Dynaudio
As far as subwoofers go, SVS has some awesome offerings, as does Axiom (their EP500 and EP600 subs, not so much the other ones). Velodyne is always a solid choice though.
For the recievers, do you really want/need HDMI? If you think you'll want it down the road, then I think it would be worth it to go for the new Yamaha unit. The MSRP is more than $1000 less than that of the Denon 4806. However, with the 4600 coming out, the prices on the 2500 are really dropping. Using the Yamaha 2500 with an external amp (like a 5 or 7 channel Outlaw or the 7 channel Emotiva amp) would yield excellent results.
Your DVD player also seems like a good choice. With new formats coming out (not sure what is and isn't coming now, but still), it wouldn't be logical to sink a ton of money into a DVD player.
So, assuming MSRP on stuff, and buying brand new...
(this is just for pricing from authorized online retailers):
Yamaha RX-V2500 $1000
Denon DVD-2910 $700
This leaves you with $5300 for speakers...that's a lot of cash. At that price level, you can put together a KILLER system. What you end up with is really your choice, but you owe it to yourself to consider the internet brands (Axiom and AV123), as they offer tremendous value. Besides, if your significant other cares about the appearance, the Rockets might be the way to go, as they are super pretty.