I actually have an XBR2 46" and haven't noticed the lag at all and I haven't put it on game mode or anything. I play through HDMI, but I'm not sure that would make a difference. I also haven't played anything that requires impeccable timing, so maybe that's why I haven't noticed.
Sony's TVs are definitely transcendant, though. I always kinda figured Samsung, Sony, and Sharp were essentially the same when it came to LCDs. But recently I got the latest 37" Samsung, and while the picture quality is great, the Sony is definitely better side by side. Is it worth the Sony premium price? Probably not, but it's not that rare that you can find both TVs at about the same price. I also prefer the Sony hardware design over the Samsung.
My Top 5:
Shadow of the Colossus, Metal Gear Solid 3, Shenmue, Skies of Arcadia, Chrono Trigger
My 2 nex-gen systems: PS3 
and Wii 
Prediction Aug '08: We see the PSP2 released fall '09. Graphically, it's basically the same as the current system. UMD drive ditched and replaced by 4-8gb on board flash memory. Other upgrades: 2nd analog nub, touchscreen, blutooth, motion sensor. Design: Flip-style or slider. Size: Think Iphone. Cost: $199. Will be profitable on day 1.
