I just picked up the Samsung PN58B540 plasma at our local SamsClub. The picture is great I would say it is about even or better then the Panasonic's of 08. The picture is super bright and super clear. Watching Sports on this set is better than LCD TV's you don't get any weird robotic motion or judder since its plasma, and your get a super bright picture. This set has all the benefits of LCD without the drawbacks like judder. Contrast and the blacks are really good. The thing that I really didn't like about the Panasonic is the amount of glare you get in a bright room. The Sammy 540 has some kind of anti glare coating which really works and is a hundred times better than the Panasonic. Also the 540 has a really nice base that swivel's, and they got rid of the TOC red color on the 540 bezel, which I really didn't care for. Also the panel is quite thin, maybe just a couple inches deep, not as thin as the LED sets but still thinner that other 58 inch sets.
The con's on the Samsung 540 is the sound quality, the speaker's sound tinny, very shallow sounding. After some adjustment, I suggest just setting them to music mode at all times which made them sound decent. But out of the box they will diffidently need to be calibrated. The standard definition picture quality is not as good as some other sets I have seen, but if you watch mostly HD feeds your good. Also plasma's and the 540 included run hot, and use more power than LCD's.
When I say calibrated I don't mean go out and spend 300 bucks for a pro to come out and do it, just pop in any Disney DVD and use the THX optimizer, or pick up a THX calibration DVD for the 30 bucks they really help.