I currently have a Bravenet account with pro hosting. I've added a few services like Classifieds and the calendar. If I register a new domain and start a new site, will I be able to register those services a second time and have the services unique to each site?
You can only have on service per account - though you can have multiple counters. If you wish to have duplicate services then you need to sign up for a another account - but you don't need to buy hosting again. Just use the second account for the other services.