I am using D'Addario EJ16s, 0.012-0.053, I know there are more durable strings than that, I might try them. I am hammering them more lately. I tried switching pick thicknesses so as to not really beat the crap out of them, but yesterday and today, I was using the thicker one (0.60 mm) and *bam*! one of them broke while I was recording. :P

I'm playing more of a rockabilly sort of thing lately. Not a big surprise to me when I think about it, as I used to really hammer the piano too.