To be completely honest Chamack is a habitual diver. He does not have many opportunities these days though.
I don't think Drogba is anywhere near up there with the worst in the PL. He "simulates" more than dives, he exaggerates the contact made and fair play to him. Being a big player you often don't get free kicks that smaller players would, thats hardly right, so you do have to exaggerate the contact. I do it myself, not diving, just bringing to everyone's attention that you've been fouled. What the likes of Eboue used to do was wrong, stick out a leg and go for contact, utterly wrong. Pires did it a couple of times to great affect also. Ashley Young is one of the worst divers in the league, he was like that at Villa too. Rooney and Gerrard stick their legs out to make contact as well, the Carroll dive, well .. I am speechless really. But none of these people even come close to Suarez. not even Klinsmann in his heyday could compete with Suarez.