Can a power user install software and allow Windows Updates?

this also gives them rights to tinker with their computers, something a one-man IT department doesn't have time to deal with when misconfigurations happen. Basically, I'd like to give them ONLY power user rights along with the ability to install software and even allow Windows Updates to occur. Can you tell me if my request is possible?

You should consider using Group Policy to deploy your applications and Windows Updates. By giving your users the rights you are considering, it would be impossible to control what software is installed and will create other administrative headaches.