1. Exactly. 2. Absolutely. 3. That's so true. 4. That's for sure. 5. I agree 100% 6. I couldn't agree with you more. 7. That's exactly what I think. / That's exactly how I feel. 8. (informal) Tell me about it! / You're telling me! 9. (informal) I'll say! 10. I suppose so. (use this phrase for weak agreement – you agree, but reluctantly) Note: Avoid the common error of saying "I'm agree" – the correct phrase is "I agree" or "I'm in agreement" – the second one is more formal.
Conan O Brien seems to have more bad looking photos than good ones floating around the Internet these days, and here is one he took with comedian Paul Rudd, who looks like he s still brandishing his Brian Fantanna moustache from Anchorman or Anchorman 2.