Of the ones you've listed, the Panny is the winner in most A/V circles. If you go Plasma, just don't forget to burn it in for 100 hours.
I bought a 50 in Toshiba Regza in December, and it is absolutely amazing. I chose it over Panny, Sony and Samsung. Money was not the issue...it was just a superior TV. I think the price has come down to approximately your range. Check that out too, as it is the 1080p, 120mhz.