What's a good substitute for Cointreau in a Cosmopolitan?

[otterlyslick]

I ran out of Cointreau, and I'm wondering what I can use instead for my Cosmopolitan. Any good substitutes that work just as well? I'd love to hear what you've tried and how it turned out.

 

[Marich]

Oh, no Cointreau? You can totally use Triple Sec or even orange juice for a similar vibe—still delicious!