My personal favorite and idea of a best bug is an arachnid - if I can get away with calling an arachnid a bug. In Minnesota their webs are good at aiding in mosquito control. We need more webs.
Here are some pics that include a pic of my own favorite and James Pulley's (ToJP) best bug. ToJP's best bug is showing how bugs get introduced. This is proof that there will always be bugs and that testing will always be needed.
[i]Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it.</i]- Brian W. Kernighan