My main viewing will be DVDs/Netflix and TV from FiOS on TiVo Premiere and either a HTPC or 360 as an extender. I do a little gaming also but not much and other than MMA we watch more movies than sports. I have no real plans to jump to Blu ray yet though the new set may motivate me.
Yeah I will have some ambient light though most of my viewing will be at night except on the weekends. Luckily I only have a gigantic sliding glass door off to the side. I am sure once I figure out what I need to block it will be done pretty quickly to minimize glare though getting the room pitch black will be tough since it is open to the kitchen. The rising blacks I am less concerned about than the floating blacks from description since I would notice that more than something over time. While I am not a true videophile I do seem to be sensitive to some of these things like the LCD motion which is why I have stuck with my CRTs so far.
The reason I am leaning 54 is we sit about 13 feet back from the TV. The way the room is setup, which is long but narrow like 12'x26' iirc, it is just too tough to sit closer without blocking access to one section of the house. I would be upgrading from a 36" CRT that we currently use at that distance so anything will be larger. I could probably jump up to the 54G20/25 but with it being in the same price range as the 58V10 I almost wonder if I am better doing that. This is of course why I keep going in circles on my decision
I ruled out the others based off 2009 which is when I started looking into upgrading. Of course you are correct with the 2010 this might change. I know when I looked I always preferred the Panasonics over the Samsung models in store which I know isn't the best place to judge but it is my only option. I need to go back and look again since the 2010 models are coming out.