B&A Novelists: Have you thought of a title for your novel yet...or even a "working title"?

Since I never intend on having any of my stories published (although someday I might write in a slightly different genre and possibly pursue publishing... anyway...) I never really take the time to come up with titles for my stories. The two long ones I've finished still haven't really been long enough to be novels either, although the one I'm currently working on is shaping up to be a giant. For organizational purposes, aka Microsoft Word save prompt, I title them with the name of my MC and then whatever villain/organization she happens to be battling in that particular story. My current story is simply titled "Ziva vs. Dasaro" -- he's the main antagonist who framed her for an assassination. The last one I finished was "Ziva vs. Dakiti" -- it was the location of a research facility that was experimenting on and killing members of her species (and yes I have a terrible habit of making all of my bad-guy-related stuff start with the letter D). I've played around with real titles before but I've never been able to come up with anything that really works. I've realized that my stories don't really have a central theme to them, which is what titles are usually related to -- if there is a theme, I have yet to figure it out.