Conflict markers in mergetool $LOCAL ?

Hello. I'm a recent convert from Mercurial; I'm enjoying the transition and am feeling pretty comfortable with most of Git. However, I haven't used mergetool much yet because it puts conflict markers in the "ours" pane -- but (even after a chat in #git on IRC) I'm not sure if that is intended behavior or if my setup is broken. I would appreciate some guidance.

For small conflicts, I like the conflict markers and simply editing the conflicted file with Vim. For files with lots of conflicts I would like to use vimdiff but I wouldn't expect the conflict markers to appear there -- it's redundant information in a 3-way merge.

Is there a better Git Way (TM) that I'm missing? Is my Git setup borked somehow?

I have the following in my ~/.gitconfig and a stock Git installation on Arch Linux.

[merge]
    tool = vimdiff

[mergetool "vimdiff"]
    cmd = vimdiff
    trustExitCode = true