Good job man
. Keep going, don't be afraid of the OC!! Just keep you're temps under watch, and don't use more vcore than you need
. It's more the volts than the speed, for shortening life of the cpu. But like they said, don't worry about it, even with the effects of OC'ing (done correctly), it should last for a quite awhile. It will be obsolete before it dies from OC, unless you don't do it right, like too much vcore with bad temps or something.
You have pretty good temps so like waxshop said you can do 1.6v if you want, temps permitting, but don't unless you need it. That's kinda the upper threshold, unless you get insanely good cooling. Lower the better usually, for both temps and cpu life. But ya, don't be afraid to up the vcore some either, even to 1.6 if you need it, it's not going to kill your cpu unless you go too high. Nice thing about these core2's is, most of the time you can already get a nice chunky OC, before you even need to up vcore much.
Looking good though man, keep it up!