It's this one.
It's not a titan, it's not expensive, it's just a shitfit battleship. What makes it special is how he died: A single volley from yours truly.
(yes there are other people on the killmail, no they didn't do damage)
Volleying a battleship (EDIT: With guns, doomday doesn't count) is something that doesn't happen very often, even for titan pilots. A properly fitted battleship has more EHP than any titan can deal in a single gun volley (except sometimes the ragnarok). What allowed this kill to happen is the fact that the battleship was not properly fitted, allowing my naglfar's alpha (about 40k) to exceed its' EHP. Not many people can claim to have volleyed a battleship, and I am still vaguely smug about it.
I didn't post about it at the time because I was still being all :secret: on account of being in a 0.0 elitepvp alliance filled mostly with dicks, but I saw a nice kill today and it came to mind.
While we're on the subject of the naglfar, I'd just like to mention that I love the guns on that thing. The alpha is great, and they're also oddly good at picking off targets with low angular velocity. I once got three pod kills in a row (like this one) at a range of 150 km. Another time I killed a stealth bomber that was doing a bomb run.
...sorry, bit of a memory lane trip there. Here's to hoping they make dreads useful again.