The tab autocompletion in Powershell has, by default, the same annoying behaviour as cmd. Fortunately, Powershell has a TabExtension function. The nice folks at PowerTab have written a richer tab extension similar to the intellisense found in Visual Studio.
I just grab the latest copy of the module and put it into C:\Windows\System32\WindowsPowerShell\v1.0\Modules. This way it always loads for every user. In the first startup I just took the default settings in the configuration wizard. It took a couple of minutes to build and that was it.