LCD edges it in practical scenarios.
Samsung are excellent units, but do use the recommended settings founf on line (e.g. avforums).
I am surprised that some on here think that digital trickery such as image enhancement and sharpness settings can do any good to any picture so turn them all off!
And seperat component might edge over HDMI....if you could find a true HD component source in the first place (and even then its VERY questionable).
And why bugger around ever feeding video through an amp?
Only advantage with in hdmi amp i could see was it saved selecting your sound source to match the video.
Idea being, 1 hdmi cable to tv, then plug all else into the hdmi amp and select your single source from there. Audio and video is then selected at once. Much like the old media box's on previous pioneer panels. Also means you only need one socket to cover all eventualitys on the tv, an hdmi socket.
The onkyo hdmi amp i tried, was flawed though as it claimed to upscale, but it did so to a level lower than the picture quality i already had, and its menu was displayed in 4by3, not wide screen. So half a step forward and 5 steps back imho.
Lcd v plasma? I've yet to see lcd beet plasma re picture quality on comparable panels. However lcd is a good bit cheaper to make, if inferior slightly in quality to plasma. No experience of LED, although i hear its so vibrant as to be unrealistic, only what i hear though.