What should I say?

[median]

Hi.
I'm an atheist, and I can't lie about it anymore. While I wouldn't go shout, "I don't believe in God," I most certainly will say my beliefs (or lack thereof) when asked. So, can anyone list me the most common Christian defenses and the most appropriate atheist reasoning for each defense? I almost got into a debate with my classmate today, but I got speechless when I can't tell her how blind she is when she said, "Just look around you. Isn't that enough proof?" I know--meaningless. Fortunately, I didn't loose her.
I do not like debates, and would prefer my belief to be left alone. However, I'd like to be prepared, as I would like to be able to at least defend my atheism, as they are able to defend their Christianism with such meaningless thoughts.
Thanks, everybody. You all rock

Thanks for sharing! Your best bet is to study the Informal Logical Fallacies, and be able to recognize them when you see/hear them. Here are some places to start:

http://www.fallacyfiles.org/resource.html
http://www.drury.edu/ess/logic/informal/overview.html
http://philosophy.lander.edu/logic/fallacy_topics.html

http://www.youtube.com/watch?v=GNeagdJd4rU

Intro to Critical Thinking
http://www.youtube.com/watch?v=CZhopF_9900
http://www.youtube.com/watch?v=6M19q1oAXko
http://www.youtube.com/watch?v=yA7fGAYJQvo

Qualia Soup's Channel - (absolutely awesome)

http://www.youtube.com/watch?v=6OLPL5p0fMg