Well, that depends on what kind of inputs your plasma will have. Most newer plasmas support HDMI. Since HDMI will support up to 1080i video, you'll be future proofed (at least for awhile). This will necessitate having a DVD player and Receiver with HDMI interface.
You might also want to pre-wire for speakers while you're at it. I would suggest that you prewire with either 10ga or 12ga Belden speaker cable. These will give you nice, low resistance connections.
Welcome to the forum, and keep the questions coming.