I'd rank LCD manufacturers in this order:
Sony
Samsung
Sharp
Though be warned, the Sony's come with a nice premium.
Plasmas:
Pioneer
Panasonic
Samsung
However, the Samsungs tend to be a bit better at displaying SD material than the Pioneers and Pannies.
LCD:
Pros:
No image retention
Low power usage
Cons:
Jaggiez on 480p material
Not very deep blacks
Plasma:
Pros:
Excellent contrast, very deep blacks
No jaggies on 480p material
Cons:
Possibility of image retention (isn't permanent)
High power usage
In the end, assuming money is no object, I'd recommend a Sony XBR4 (LCD) or a Samsung FP-T5 (plasma). Maybe a Pioneer Kuro. The Kuros are the best for HD material, but I've heard (very minor) complaints about their SD output.
We have an XBR4, and I couldn't be happier with it. :)
