For me, it depends on exactly how depressing I want to be that day. Usually I like one dead and the other in mourning because it's just so heartwrenching. Sometimes, I like Severus alone and depressed for whatever reason I can think of. I don't think I've ever written anything where they both died. Hmmm... *ideas*
But, yes, that's an interesting discussion topic.
Sorry about the sadness but I'm glad you liked it! And thank you. :)