[Analyst]

LCDs: Sharp, and it isn't close though a few others are OK; some are truly junk
Plasma: Panasonic, and only Pioneer comes particularly close

It's far from just being the panel (and Sharp/Panasonic make their own, as do a number of the brand name companies); the display processing electronics make a huge difference.

One thing to keep in mind is that while LCDs can look insanely good (not some brands, though) on HD and DVD signals, they don't look that good on plain ol' broadcast TV signals. If you're mainly watching HD and/or DVD, LCD or plasma is the way to go but if you're just going to watch regular TV, then I'd hold off a couple more years and stick with a cheapy tube for the meanwhile.