bturville: there is still a difference. Take Santa Claus for example, he was said to reside in the Arctic, however, human have explored the arctic and reported no Santa nor Elves. that is 'sufficient evidence'. The others can be explained similarly
God, on the other hand, is quite complicated. Creation of the universe, the Big Bang, has too many unknown things about it. When these phenomenon can be explained by science [and science alone], then we can safely say that there isn't necessarily a God, at that point, agnostics would no longer exist, there is sufficient evidence [and a new faction would be created, those who don't believe in science, nor God, and sit on the fence]
it is true that we are not obliged to accept existence of everything, but nor should we automatically deny, especially on the topic of God which can sway both ways.