As a general rule:
You: Jumpseat benefits + space available travel on your own carrier and affiliated mainline for free or small surcharge. Additional travel at reduced rates (ID90/ID80/zonal fares/etc) on other carriers based on company agreements.
Spouse/Parents/Children: Space available travel on your own carrier and affiliated mainline for free or small surcharge. Additional travel at reduced rates (ID90/ID80/zonal fares/etc) on other carriers based on company agreements.
Parents may pay higher premiums for travel.
Some carriers will also allow employees to designate a "domestic partner" or an unrelated "travel partner" for unmarried folks.
Don't forget to consider "buddy pass" arrangements too. For example, Piedmont Airlines employees can get buddy passes for friends on USAirways mainline at a reduced rate. Nice benefit if you ever want to travel with other non-aviation friends.