For me, it's definitely SAIS.
They sent the admission letters on March 20th, 2009 and all rej letters come in early April. Still one month to go.
Hope you've heard good news from UCSD.
FYI
I received the provisional admit letter on Feb. 5th, 2010 (UTC+8).
I submitted my online application on Nov.23rd, 2009, and later mailed my official transcript(from Beijing). The Office notified the completion of application on Dec. 12th, 2009.