I see your, “Many years later [...]" and raise you, “It was the day my grandmother exploded." Iain Banks, The Crow Road.
Merely goes for the surprise element.
The other quote also:
1) gives more plot information (the hero is an older man, sentenced to death),
2) beautifully evokes his nostalgia before death (remembering an event from his childhood)
3) AND builds suspense: He is at the moment in front of the firing squad. Will he die? Get a pardon? Somehow be resqued?
"The last man on Earth sat alone in a room. There was a knock on the door...".
http://en.wikipedia.org/wiki/Espedair_Street
Edit - having said that, I think the start of The Crow Road is rather good as that immature desire to shock is rather appropriate for Prentice McHoan - but you can't really tell how appropriate that is until you've read more of the book.