If you feel you need more health, go VIT. If you feel like you've got enough health, go STR.

STR will help for aggro generation early on where it's usually a bit shaky. Later on, it loses its value as an aggro generation tool and is instead used to increase DPS.

VIT will... well, give you more health.

If you can keep your gear up to date regularly, I'd definitely recommend STR. Don't be afraid to throw some in VIT if you need it, though - you can always change them later.