Who played Ari Gold in 'Entourage'?

In which TV series is Lynette Scavo a main character? Who played Veronica Mars in 'Veronica Mars'? Who played Vincent Chase in 'Entourage'? In which TV series is Vincent Chase a main character? In which TV series is Ari Gold a main character? Who played Meredith Grey in 'Grey's Anatomy'? Who played Derek Shepherd in 'Grey's Anatomy'? Who played Cristina Yang in 'Grey's Anatomy'?