Best way to re-do a CVS repository with git?

I have a large CVS repository (1.5 GB without its history) that I'd like to convert to git, but I'm not sure about the right way to set it up. If I need to change the way I'm thinking about source code management, that's fine too, but here's what I have today in a single CVS repository:

MyProject
   Apps                 # Only apps people use this.
   Common               # Everyone uses this.
   Firmware             # Only firmware people use this.
   External/ProjectA    # Only app people use this.
   External/ProjectB    # Everyone uses this.
   External/ProjectC    # Only firmware people use this. This is 1 GB
of code by itself.

I manage this today with CVS modules, one for apps people and one for firmware people (and another CVS module with everything for people like me that work on both).

I initially thought I'd create separate git repositories for each piece, but I'm not sure how that would work when it comes to tagging an entire release (i.e. a tag that spans multiple repositories). Or how it would handle a git repository within a directory managed by another git repository.

What's the best way to set up something like this with git?