I understand where you are coming from on Hillary. However, because of her high negatives and Bill's reputation and sloppy record, I think enough Democrats in Congress would ally themselves with Republicans to hold her (and Bill) in check - not totally, but enough so your worst fears wouldn't materialize.
On the other hand, precisely because he is a "blank slate" (in multiple senses of the term!), Obama might get away with stuff the Clinton's couldn't. He would probably get a far longer "honeymoon" than Hillary would get because of her "experience" claim!!
As I said in another post: "On national security, my major concern if we have a Democrat President, I think Hillary is the stronger - not great mind you, but far stronger and more pragmatic than O'bama."
Hopefully your wrong on conservatives staying home. either alternative the Democrats offer is far worse to contemplate than a not-very-conservative McCain.