Let's see:
Helpdesk, no real stress, shift work, when you are done you go home for the day.
Helpdesk Manager, a bit more stress, higher responsibility, have to deal with complaints, hire/fire people and manage both the customer and your people. But still mostly go home on time.
System Administrator, can be stressful, when things go wrong you are definitely on the hot seat. Usually on call, can be very bad to get a late night phone call. Virtualization of servers and data centers with redundancy have improved this some.
Network Engineer, similar to System Administrator, there may be more travel as once a network is up they will want to use your expertise elsewhere. The higher up the money chain you get, the more travel you should expect.
Project Manager, similar to Helpdesk Manager, except higher stakes, a bit more stress. At certain companies you are also required to help on proposals and getting new work. These duties come on top of your day job.
