Where do I start with a home theater system?

I have a 2 channel system. Ive never wanted a home theater system. Recently Ive decided to try it out, but I dont know where to begin. My stereo consist of a Mark Levinson #23 amp, a Classe DR-5 pre-amp, Theta DAC and transport, Yankee planars and Acoustat speakers, and other items. Being these items are old school can they be used in a home theater or should I start with everything new[up to date but not new]. I just brought a Panasonic 50" plasma television. Since I dont know if Ill like it I dont want to go real high end. Thanks for your help. Jim