chloe katherine shea cal henry jimmy abby

I think the casting directors did an amazing job. My favourite acting performances were Henry, Trish, Abby, Jimmy, Cal, Chloe, JD, Shea, Madison, Sheriff Mills, Shane, and Wakefield because the actors all made lovable characters (mostly, with the exception of Wakefield) out of stereotypes I usually loathe(rich girl, stuck-up frat guy, ex-boyfriend, blond flirt, etc.) and they were all my favourite characters.

Also...Abby, Jimmy, Cal, Chloe, Sully, Danny, Booth, Malcolm, and Madison were all played by the same actors in the presentation and they were the only people who stayed on with the show (because the casting directors and crew liked them).
There's a trailer of it on YouTube called: "Harper's Island presentation." You should check it out - you'll recognize 9 characters.