Personally, I love every wildlife guy that ever had a show.
Cousteau was the greatest in my opinion, but I was always a fan of even guys like old Marlin Perkins on Mutual of Omaha Wild Kingdom - and that old dude really had some staged wrestling fights with lions and huge crocs that you just knew were tranqued and probably senile with thier teeth pulled out, it was almost funny, but still, you learned a lot watching.
There was a really cool wildlife show a few years back that I forgot the name of, but it was actually more entertaining than Irwin's show. It had a gnarly, skinny old Aussie guy - can't remember his name, he was always eating wierd stuff in the outback with his incredibaly dirty hands and fingernails, they sometimes showed him walking around in his underpants bathing in streams. He was always getting bitten, stung or poisoned by something, but it didn't seem to phase him. Could anybody tell me the name of that guy or name of the show?