Let me tell you my story.
I grew up catholic. Up until I was 14, it wasn't an issue for me. Then I met
a born-again christian, a very sweet person, not proseletyzing(sp?), not 
imposing. I tried to get into being as christian as I could, as I felt I 
'should'.

But the more I tried, the more depressed I got. I felt guilty for some of my
own personal, honest feelings. I tried so hard to reconcile this conflict.
until I was 23.

Then I taught myself to think rationally. I read a lot of books, pro and con 
religion in general and, specifically, catholicism. I came to a crisis point,
then it finally clicked and now I am a staunch atheist. 

This is a very loose explanation, but it's the gist of it.

Now, (at 26) I feel better about myself, better self-esteem, a generally 
stronger person. I have well-defined goals. I have a strong and stable sense 
of morals and values. I am not a neo-nazi or a corrupt politicain, etc. I 
believe in human rights and 'live and let live' among other things. I am very 
anti-violent and anti-hatred. (This is to debunk the myth that atheists are
depraved.)
Religion has no place in my system.
Tough.

Bertrand Russell said that we cannot *know* god doesn't exist, we can't prove 
it. So, in that sense, we can only truly be agnostic. But, for all practical
purposes there is no god.