Now that there is a PowerShell project type in Visual Studio, what do you want to get out of it? Here are some of my ideas. I'd love to here some more!
MSBuild Targets Support and Properties Dialog
Allow for copying scripts and referenced assemblies, create module manifests, sign scripts, or any other packaging related mechanisms.
Add Reference Dialog Support
Reference other managed project types or assemblies
This would auto-load the output into the PowerShell runspace for the PowerShell project automatically. It could also copy the assembly output into the PowerShell project's output directory.
Reference modules and snap-ins
The dialog could expose functionality that could reference other modules and snapins so they are auto-loaded into the runspace at run time.
Make it extensible
Allow for more reference types. For example, internet references. With this type of reference you could integrate into PoshCode.org and download and reference scripts directly into projects. I'm thinking NuGet eventually....
What do you want out of the project system?