Well, after a long day of shopping yesterday, I came home with an LG 42LH30. I looked and tested a lot of panels. I don't know if you guys have an HHGregg in your area, but the sales guy there were great! I went in with a list of 4 sets that I wanted to see, told them what the primary use was going to be, and those guys pulled those sets off the floor, hooked up their demo PS3's they had, and we actually gamed it up for about 45 minutes.
We played the GOW3 E3 demo, unreal tournament 3, and guitar hero world tour. Out of the 4 sets we had set up, the LG and the Panny were the ones that I could did not visually notice any lag. The Samsung LED the one guy insisted we put up there was the worst, and very noticeable. Unreal 3 was almost unplayable, even against the AI bots, so online game play would be a nightmare. The Toshiba, I don't remember the model number, but it was "240hz" model, wasn't bad in game mode. You would notice a little lag in game, but I think compounded with net connection lag, it would have made things very difficult.
They obviously didn't have the 42" Panny LCD that was on top of my list, since it's a BB exclusive. I actually went to BB and looked at this TV for a good hour, and played with the limited setting options it had. Even with a direct connected Blu Ray, the picture was no where close to even the Insignia's it was set up next to. It just was not worth the price tag to me, and being there almost an hour with a big wad of money in my pocket, not one sales guy stopped and asked me if I needed help with anything. I really do not like that store.
I haven't got the TV set up yet, just unboxed and tested to make sure everything was working. Waiting on my stand to be delivered today so I can get it put together and everything set up so I can get my game on! Even if there is a little bit of lag on this set, I don't think it will be anything I can't overcome by adjusting my play a little bit. I usually have a really good net connection and can connect at under 50ms.
I'll post back more results later if anyone is interested!