Your topic is a revenue-generating tool, and an introduction for potential visitors. You don't want to turn people off with it, and you always want to give members a reason to tip you.
What would interests me as a perv would be a combination of:
A greeting or theme, if you have one for the session.
A short-term shopping list (flash, dance, pick song, etc.)
A long-term goal (countdown), if you do those.
Daily deals, if you regularly sell videos or photos.
Different topics work differently depending on your personality, how popular you are, and the kind of members you attract. I'd poke around successful models you emulate, who run their rooms like you would like to, and see what works for them. Just bear in mind that on some nights, nothing works.