How do you respond to 'tu es tres sympathique?

"tu es très sympathique" means you are very nice. You can answer many things:
- merci beaucoup (thank you very much) would be the easiest
- merci, c'est la journée des compliments (thanks, seems to be compliment's day)
- vous avez besoin de quelque chose (do you need something?)
or anything else adapted to the situation.