If you've narrowed it down to those three, you have to decide which pros and cons of each are most important to you (I love to state the obvious
).
1) Bigger is almost always better when you're going to be watching a lot of movies
2) Warranty length and reliability reputation should play a factor
3) If you play a lot of games and/or watch a lot of fast action sports (hockey, racing, etc.), you may want to lean toward the plasmas (I know, LCDs have improved in these areas, but I'm still partial to plasmas)
4) Are you going to calibrate these yourself with a DVE or Avia disc, or have a professional calibrator come over? If professional, being able to get into menus to change gamma levels, color management, etc. will help you achieve a more accurate picture, and some models allow more access to those menus/options than others.
5) Are you going to be using external audio, i.e. a receiver and surround speakers, or are you going to be sticking with the TV speakers? If no surround sound, make sure you're happy with the audio of the TV you pick (otherwise, not a factor).
Personally, if I had to pick, I tend toward Pioneer or Panasonic plasmas, but the size of the Samsung plasma would offer a slightly better movie experience. I'd probably still go with the Panasonic plasma, though, unless I could save a little more and get a Panny in a 60". I'm sure you'll get more advice from owners of those three models (I have a pioneer kuro upstairs and a Panasonic front projector downstairs). I'm just hoping to give you a couple more things to consider, since you're the one that needs to be happy with your choice.
Good luck!

1) Bigger is almost always better when you're going to be watching a lot of movies
2) Warranty length and reliability reputation should play a factor
3) If you play a lot of games and/or watch a lot of fast action sports (hockey, racing, etc.), you may want to lean toward the plasmas (I know, LCDs have improved in these areas, but I'm still partial to plasmas)
4) Are you going to calibrate these yourself with a DVE or Avia disc, or have a professional calibrator come over? If professional, being able to get into menus to change gamma levels, color management, etc. will help you achieve a more accurate picture, and some models allow more access to those menus/options than others.
5) Are you going to be using external audio, i.e. a receiver and surround speakers, or are you going to be sticking with the TV speakers? If no surround sound, make sure you're happy with the audio of the TV you pick (otherwise, not a factor).
Personally, if I had to pick, I tend toward Pioneer or Panasonic plasmas, but the size of the Samsung plasma would offer a slightly better movie experience. I'd probably still go with the Panasonic plasma, though, unless I could save a little more and get a Panny in a 60". I'm sure you'll get more advice from owners of those three models (I have a pioneer kuro upstairs and a Panasonic front projector downstairs). I'm just hoping to give you a couple more things to consider, since you're the one that needs to be happy with your choice.
Good luck!