Imagine that there's a box with a cat underneath it - the only cat to ever live in fact. I believe that cats exist because others have told me and I've accepted it on faith based on the fact that its reasonable and that I really want to own one. From the sound of it they're a lot of fun. Because I've accepted it, I can hear it meow. You see, people who don't think cats exist don't believe that the meowing could be caused by the cat, so they attribute it to the box or to their mind playing tricks on them.
An anti-cat believer comes up to me and suggests that my belief in the existence of cats is unfounded, irrational, and unreasonable. He suggests that since we've never seen the cat, it must not exist. I respond that I have positive evidence to believe the cat exists - I've heard something I can only attribute to the cat.
The overall point behind this scenario is that I think Christianity by default is more reasonable than atheism on the point of belief. I have positive evidence in the example that cats exist. The person who doesn't believe they exist has no positive evidence that they do not, only their interpretation of evidence that does exist. I think its more reasonable to base a claim on what one knows than to base an equally weighty claim on what one doesn't know.
Heh... now I need to know if any of that made sense.