I'm convinced things like git will need to include bugtracker capabilities at some point. A commit log is one thing, but internalizing decision matrixes and issue reports will be important to not repeating the mistakes of the past 4 decades. We need to keep the history with the history and a 1-3 line commit message will not explain everything for the devs that come 3 decades later.
Oh certainly: I would /hate/ my version control software locking me into a particular bug tracking methodology. However, I think in the same way the browser has become the standard runtime for most applications that we will need to join version control and bugtracking together to preserve "all the history". The next frontier is someone layering bugtracking on top of something like git, so software archaeologists won't be abundant. :-)
Are there any bug trackers that use git as their data storage? Would be cool to bundle that up as a subrepo or something, so it can get carried along with the code repo, and also allow writing up bugs, fixes, etc... while offline to be synced later.