Sounds great Oferlaor, but its just not true in practice.
I see quite noticeable flicker on my TH-42PW3 in several situations. Certainly in bright daylight viewing, its quite noticeable. Not as bad as a 50Hz or 60Hz CRT certainly, but still there.
You also get line twitter, which many people regard as flicker. The de-interlacing is pretty good, but its not perfect; especially with video - as opposed to film - sources. Thin horizontal lines and some text can be seen to flicker quite badly because of line twitter. Just look at the "sharpness" test patterns in Video Essentials, for example. You would think you were watching an interlaced display!
Now is any of this a problem? Not really. But to say "With all plasmas ... there is no flicker with any signal" is completely untrue.
Cheers,
Chip