It's a dedicated box, so I don't see the point of using a cache program.
Backing up the DBs is important. Using a plugin like Brujah mentioned or script to do this automatically is a great idea.
You should consider protecting your admin areas. Main thing is change the admin username.
http://www.thechetan.com/2008/11/mak...cking-attacks/
Change your wp_ default table name
http://blogsecurity.net/wordpress/tool-130707