Keeping my iPad 1 (but giving it to my wife) and getting the mini, if it comes out. If not, I'm getting a Nexus 7 and keeping my iPad 1 for my own use.
Since the mini hasn't been released yet and we don't yet know the exact specs for sure, I don't think one could say that going from the current iPad models to the mini would necessarily be an "upgrade".
For example, if the mini doesn't have LTE, a retina screen and a processor that is more powerful than the current iPad -- I'd say it would be more of a downgrade. Although, one that might make sense if you need a smaller tablet.
How can we respond to this poll? The iPad mini isn't official. If it does get released, we still don't know the specs. Without this information, we can't respond properly.