Am I secure enough from a hack?

Hi guys, I'm just about to launch on Monday and this is my number 1 concern! I would hate to get hacked. I use a private server so I'm not on shared hosting, I have pretty good passwords I think and I have WP secure installed with all of the default settings including login lockdown after 5 false password attempts.

I back up using the S3 backup plugin. This backs up;

Config file
Database dump
Themes folder
Plugins folder
Uploaded content

Do I need to back anything else up and could my host backup from these files that S3 backup takes or do I need to do a full backup through cpanel?

Any ideas as I want to be as safe as I can be. My one concern was the 'group docs' plugin I use. I have it set to only enable PDF, TXT and WORD docs. Could anything malicious be uploaded and executed through this way?

Thanks so much,
Ross