Welcome to Ozformers. In regards to what toylines to focus on, if you want to collect locally than I suggest the Generations toyline (old/new toys being refreshed with modern engineering from all era's of transformers). If you have more of a budget and intend to purchase online, than the masterpiece line (highly detailed and articulate toys). The WFC/FOC toys are also good and fun to collect. Alternatively you can just pick and choose whatever toy looks fun and cool for you.