First off, I love these threads.
I spent a long time trying to find the right HDTV for next gen games (this was prior to the Xbox 360, Wii and PS3 coming out).
Thanks to forums like AVS and NeoGAF, I was able to do my research and at the beginning of this generation I bought a Panasonic G15 50" Plasma.
Now most people tell you that you should run slides or whatever to "break in" the television but I didn't end up doing that.
What I did do was I made sure to not put brightness or contrast past level 50 for the first 200 hours or so of using the set (because the risk of IR and burn in was higher).
After about 200 hours of nothing but pure gaming (something they warn you against doing) I was able to tune the settings to get the best picture out of my set.
I play fighting games, music rhythm games, games in standard def - the set handled it all.
I love plasma so much I upgraded it to a Panasonic GT30 50" plasma after the fact.
Only downside is that the IR is a bit worse with the newer plasma but nothing worth getting upset over.
In the end the choice is yours but honestly - Plasma is phenomenal tech.
Low input lag, amazing picture, great value. What more can you ask for?