I was considering the Robocop, but after seeing pics I felt like something was off about it. It looks short and fat in the pics.
If you buy Anakin and Luke, you have a good start on the Star Wars PF's, which would lead to you wanting Vader, Boba...etc.
If you buy Aragorn and Indy, you have the start of a more diverse collection. One that you could add the Terminator or Leonidas to later.
The point is, once you start buying them, you won't be able to stop. Trust me, I started with Ash, and the minute I opened it I was hooked. I now have Ash, plus I ordered Indy, Leonidas, Aragorn and the Terminator.