I heard somewhere that Marth's taunt was "Everyone, look at me!" but I'm not too sure what their VS. victory sayings are...*checks the source with above infor*
Apparently, there are three different VS. Victory poses for each character.
MARTH
1)"Boku wa makeru wake-ni wa ikanainda!"
Translated: "There's no way I can lose."
2)"Konkai wa boku no kachi da ne?"
Translated: "Doesn't it seem I am the victor?"
3)"Kyou mo ikinobiru koto ga dekita."
Translated: "Today, I have survived."
ROY
1)"Mamoru dekimono no tame ni... makerarenai!"
Translated: "For those I protect... I can't lose!"
2)"Kurushii tatakai datta."
Translated: "It was a tough battle."
3)"Shin no tatakai wa... korekare da!"
Translated: "The true battle... begins here!"