Do I need power conditioning for my new plasma?

No more nor any less than you need for your other components. A good whole-house surge protector is important for any house.

For video displays, you should also consider a local surge protector as well as surge protection on any video input signal lines (from, say cable or satellite).

Kal

It all depends on how critical your eyes are. Just like listening to music: A lot of people can't hear the differences that a good power conditioner makes(definition, bass tautness, soundstaging, less grain/more extention and transparency), and think those of us that CAN hear the difference are nuts. Get a Richard Grey's Power Company, or Shunyata conditioner(audition, if possible)and see for yourself whether it's worth it. All conditioners offer some surge protection, BTW.