Gaming systems always should make people a bit wary of plasma displays. In my experience though, Samsung plasmas simply look awful unless they are fed a good HD source. A good thing to do is try different sources than HD and/or DVD and see how they look on the displays. I JUST went display shopping as my brother wants something in the 50-60 inch size range. Upon close inspection of about half a dozen plasmas, most playing different sources, the most notable issue was false contouring. This effect occurs frequently in skin tones, and on skies - where there should be a smooth transition from light blue to medium blue, but instead, there is a sharp jump from one color blue to another. The effect is similar to dithering. I have never seen a plasma that deals with false contouring perfectly...
But, plasmas put out a good amount of light and have that 4" depth that is so very cool. Aesthetics are often a very good reason to buy into plasma. Image quality - is rarely as good as DLP, LCD, or LCoS. Likewise, you won't get full 1080p support with that Samsung I don't believe.
The NEW Sony SXRD displays (LCoS) should be a minor upgrade over last years models. You get full 1080p plus support for 1080p on the inputs. As well, the big 'wing' side speakers have been put under the display in a more distinguished fashion so if you are using your own 'real' speakers, the Sony's won't be as obnoxious. Sony processing of images is far better than the Samsung... and I had not heard lamp life issues, but it is worth determining that in your budget.
Samsung DLP... They look alight IMO, but simply don't have the image processing that the Sony does. Likewise, only a few of the newest models will have 1080p support.
FYI: I own 2 plasmas - a Sampo and a Samsung. The Samsung is, at best, alright. Had I the cash, I would have gone with a Pioneer, but no cash. The Sampo... is cheap.
If your space happily permits a rear projection television, then I would pretty much immediately disregard plasma as a choice. You get a better image, for a much better price, with rear projection technologies.
WHAT IS YOUR SEATING DISTANCE? Most people tend to go with a display that is far to small for their seating distance. Yeah, it looks big for the first month, but then you begin to wish you had gone bigger. In a store, with a larger display (60" or so) sit at the distance you will actually be in your media room. Sit for at least five minutes and relax... see how you like the size after that time period.