From the artikel from the link that berkata "Couples 2009" above. This is what they say about CB. Seems interesting and yet heartbreaking:

#6 Chuck and Blair
“Three words, eight letters. Say it and I’m yours.” Blair and Chuck are definitely the most interesting part of Gossip Girl. Their chemistry is electric and yet, they are probably the one couple on this senarai that could be together but (most of the time) mutually agree that they shouldn’t. Both believe their passion comes largely from messing with one another’s lives and neither can give up their self-absorbent lifestyles. It seemed Blair was willing, but Chuck can’t seem to give up his old Playboy ways and potentially will never change.
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Awww! *tear*

Let me know if you've discovered any others! ;p

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Gossip Girl Actors/Actresses B-DAYS!!! (and their teen characters. ;p)
1.
Ed Westwick—June 27, 1987
(Chuck Bass)—May 19, 1991

2.
Leighton Meester—April 9, 1986
(Blair Waldorf)—November 17, 1990

3.
Chase Crawford—July 18, 1985
(Nathaniel Archibald)--???

4.
Blake Lively—August 25, 1987
(Serena van der Woodsen—July 14

5.
Penn Badgley—November 1, 1986
(Dan Humphrey)--???

6.
Jessica Szohr—March 31, 1985
(Vanessa Abrams)--???

7.
Taylor Momsen—July 26, 1993
(Jennifer/Jenny Humphrey)--???