Britney was the one who immediately came to mind. It's like she laughs with her entire body and her entire face kind of lights up and it just can't be contained. Especially when you go back to 2001-03 she just seemed to kind of light up. I would say she probably has one of the most distinctive smiles in Hollywood. You just see everything light up and her cheeks get so chunky. lol.
Rihanna's laugh is adorable when she makes that high squeeky sound. It just seems like she is enjoying herself a lot and can't contain those happy kind of sounds.