Direct sunlight even kills off the best anti-glare HDTVs. There is a minimal amount of light control required for ample viewing, even with generally better performing LCD HDTV models under bright conditions. Also, the larger the panel, the more glare/reflections will generally be involved with such a large, flat piece of glass. If your light is bright but indirect and generally bright, LCD or LED-LCD might fare better. In a dark space however, e.g. when you're watching movies at night, plasma will basically spank the daylights out of the other two.
I have a big glare problem during daylight. In chosing a LCD or Plasma which brand or models reduce glare?