You'll need lots of room and lots of money for this hobby. Decide which items you want to collect.
Action figures are popular and take up less space than vehicles.
Ornaments have been released every year starting in 1991. Be willing to shell out some cash - this stuff isn't cheap. Scope out the exclusive releases from Target, Kaybee Toys and ToyFare. Each store carries items exclusive to its own chain. Look at the Playmates Star Trek Product List for updates on these items.