What are the best methods & plugins you use to secure 100% from hackers & security breaches? Also, what method do you use to secure downloads?
There's no way to be 100% secure. I always use akismet, did you pass math, and bad behavior. Here's a good guide on keeping WP secure: http://maketecheasier.com/11-ways-to-secure-your-wordpress-blog/2008/08/12
Secure downloads? you mean manage them? check out the wordpress security plugins available for download. Also ensure your permissions are correct and your host has mod_security installed on apache.