Keg,
That's a loaded question. I think members are skipping over this one because of the depth of it. I'll answer a few to get this started.
Blue-ray and the Play Station 3 will be capable of 1080p reproduction. Most HD sets right now are not. Some that state 1080p aren't true 1080p, but upscale the image. Make sure you know the difference. I'm not familair with that set (strange size).
There is another major issue you will run into with the Denon (and all receivers right now). Those that offer HDMI connections are outdated 1.1 versions. You want the HDMI 1.3 version, as well as a receiver that can pass Dolby True HD/DTS HD. Those should be coming out within the next year.
In the meantime, you can pick up a reasonably priced non HDMI AVR and run your HDMI cables directly from the cable box to the flat screen (assuming your cable company has HDMI up and running-most don't). You'll still run your audio outs to the receiver. When HDMI 1.3 equipped with DTS HD/True HD is available, sell your current AVR on ebay.
Two subwoofers are extremely hard to locate in a room without room cancelling effects. Two subs usually sound best stacked on one another - which most people don't care to do. My suggestion is to get one good sub from a company who specializes in subs, and spend as much as you can afford on one. SVS/HSU/Velodyne make excellent subs.
If you have a lot of brown outs or spikes, it wouldn't hurt to spend a $100 on a decent surge protector. Just keep in mind, it wont make your system sound better, or protect from a direct lightening strike.
Buy your cables/speaker wire online. Wire is wire, and the biggest rip off is buying high end cable from high end shops.
www.cablewholesale.com is one example of many sites that sell connections for a fraction of the cost at brick/mortar shops.