Where to keep configuration for SharePoint solution

Where do I store a configuration of a sharepoint solution? The solution has a feature activated on a site collection, so there will be multiple instances of it running on a farm. Installation and feature activation will be automated with powershell because the feature needs to be activated on multiple site collections. All the instances need the same set of configuration parameters, set of keys and values. Where do I store them? A file, registry or some other place? If if is a file, is it a good idea to store it in c:\ProgramData directory?

Each instance of the solution writes logs. Is it a good idea to store the log file at c:\ProgramData as well?