Depends what people take 'iconic' to mean. Sackboy is definitely famous and very well defined, immediately identifiable. Very strong iconography with him. Many millions dressed him/her up and that's very impressionable. I'm more surprised by Agent 47. I think if you ask the everyman if they recognise these characters, Sackboy would be far more recognised than others. But of course Lara, Mario and Sonic will be tops as they have movies and a wider franchising.