Stone Age is a great introductory game into the worker placement category. Its easy to learn and teach to new players, however it still has a surprising amount of depth for more advanced players. The dice add just enough of a random element to where strategies will often need to be adjusted on the fly, but not so much that it feels at all like a luck based game. There are limited spaces for placement, so you also get that element of anticipating what other players will need, and then the satisfaction that comes from blocking them from accomplishing it :)
This game was my first introduction into the worker placement genre, and I still find myself wanting to bring it out whenever I can.