posted
The only one of your suggestions I would change is the second, which I would punctuate thus:
"_It's about to explode!_"
I include end punctuation if the entire sentence is italicised, but the quotation marks seem to me to be in a different context, so I would only italicise them if they were included themselves in text that was italicised:
_He said "tomorrow"._
[This message has been edited by Jules (edited January 14, 2005).]