You should see the oak in my parents' side yard...We had it measured and officially added to the century tree registry. It was the third largest Red Oak in the state then, and would have been the biggest if about thirty feet hadn't been blown off by lighting a few years before we moved out there.
It'* been dying ever since, about 25 years now, and it dropped two major pieces last year, a branch that was 3' through at the trunk and almost 60 feet long from trunk to twig...it drove side branches 10" thick so deep into the bed of the creek that they couldn't be budged. There has to be ten feet of branch under the soil...
It also lost another fifteen feet of the top this fall. It had been dead up there since before we moved in 18 years ago, and it finally rotted off...I'll post pics when I can find them.

EDIT: the branch that fell off last spring is the lowest on the right, pointing towards the camera. Mom says it shook the whole house...

Tell that to this guy.

http://www.humsurfer.com/roy-c-sulli...rd-seven-times

I would cut the tree down now.I had one hit a few years ago. It dies.

Actually, the cottonwood behind my parents place that was hit is still perfectly healthy. There'* a small scar at the base, but it'* still standing strong over ten years later.

It really does look like the bolt went down the outside of the bark, so the actual growing area of the tree is probably ok, and the heart wood is most likely untouched.
If it doesn't threaten the house, give it a year to see how it gets on. If you see signs of deterioration, then get it cut.