My best childhood friend was snufflespf. She is also my best adulthood friend. She's currently rocking the world and being my life hero over at Harvard.
Though Niz is the first to come to my mind, I did have two other best friends at different times in my childhood. My first best friend I met in kindergarten. She moved to Maryland after second grade but we've still kept in touch through letters. I think I might even be seeing her this weekend. That would be great as it's been more years than I can remember since I've seen her face.
The other best friend moved into the house two doors down from me the summer before fourth grade. She introduced me to Harry Potter and together we discovered the internet and experienced all the trials and tribulations of middle school. Her mom basically adopted me and they were exactly the second family I needed then. So much of who I am today is a direct result of knowing them and for that, I'll be forever grateful. Our friendship didn't really survive growing up but I'll always treasure it.