I would say [TOS] then Xanadu. Specific moments for me in each show:
Xanadu: The Andrew Lloyd Webber line had me rolling and the infamous "Bitch, I dont know your life" I have never laughed that hard. It was like my quote for the weekend.
[TOS]: when susan said "maybe you just werent meant to have children" I was dying cuz Im a sondheim freak. And every voicemail got funnier and funnier.
Both shows are the most fun/funniest times i have ever had in a theatre.
<------ Me and my friends with patti Lupone at my friends afterparty for her concert with audra mcdonald during the summer of 2007.
"I am sorry but it is an unjust world and virtue is only triumphant in theatricle performances" The Mikado