Oooh, The Moon is a Harsh Mistress is a good choice, even though the tech now feels anachronistic (except Mike). I used to put it in my starter pack too.

The Martian is an excellent starter kit choice -- extremely approachable while still being largely representative of what sci fi can be! Nice!

Tangent: I originally read The Martian while weathering a summer windstorm in the high arctic. My tent was threatening to blow away, bouncing down the tundra with me and all our supplies. It really added to the experience :)