That's kind of like asking what kind of shirt a 6'1" man should wear.
It's personal preference, as long as it fits.
I can tell you that flatwound strings won't be so great if you're playing metal, but if you just need something boring like ernie balls, just figure out what gauge you like. Besides, strings are what, $4 a pack? Go buy a few and see what works for you.
i like the hybrid slinky set better, the orange pack. it has a heavier low end, which keeps the strings from bouncing sharp
I just started using GHS 11 boomers, and the tone is a good bit better than the super/regular slinkies i was using, especially for metal. Tho i'm still getting my fingers stronger to get used to the gauge its paying off because i went to a guitar with 9's and it was so freakin easy to play.