What piece of evidence have you been successful with in debating creationists?
Gotta go with archaeoptrix on this one. Though, by saying that, I mean the whole host of fossils demonstrating feather evolution.
It's great to watch the fundies turn chicken on this topic (Could not resist!).
"It's a bird"
but it has teeth
"It's a lizard"
but it has feathers
"it's a lizard that died on top of a bird, so it looks like 1 animal but in fact it's two."
We have dozens of these fossils.
"Um, I think I left the oven on. I gotta go."
Very well then.