I'm in the same boat and am tossing up between a Panasonic and a Samsung. In Samsung's favour, they offer a plasma that is roughly the same width of the LED Backlits (1.2" compared to 1" IIRC), so that gives you the aesthetics without the price tag (Series 8 Plasmas). You also get a bunch of features like DLNA streaming/youtube - not so important if you have the XBox for that but if it's anything like my XBox, its noisy as hell.
The Panasonic has in its favour the competitive pricing and similar, if not better image quality but that'll change depending on which shop you view it.
Also, I imagine mounting would be a sinch. I've mounted a few 42" to 60"+ screens that were atleast twice as heavy as these thin screens.