Nexus Mod Manager by far. While Wyre Bash is useful for advanced stuff, it's just too early and all the required gizmos you need to get it running just to do something NMM already does just bleghs.

Python isn't needed anymore, there is a standalone version. I once wrye bash sometime back in 2007 or so, and yes that was a hassle, but now it's as easy as with NMM :V

I doubt there'll even be a mod manager. My guess is that it can put .esp files in the right folder and nothing else.