I've got two primary computers, one Mac Pro and one MacBook Pro for when I'm on the go. I've also got a Linux sever which also acts as NAS.

Currently I backup the entire computers to an external drive with Time Machine which is rather useless and doesn't sync anything. What I really want to do is to keep my important files synced between both computers and my NAS (which is running RAID 5), that way I'm not backing up easily replaceable systemfiles and I've got all my important files in 3 places where two of them are running raid so at least 5 drives would have to crash at the same time before actual data loss occur.

Folders I want to keep synced is basically my photo, documents, development, mamp and work folders and then I want to keep the user library folder backed up but not synced. I'm thinking that I'd have to use rsync but don't know how.

Before suggesting Dropbox and similar suggestions I don't want to use them because of several reasons some of them being security (Dropbox obviously proved this), Speed (sometimes I'll sync gigabytes of data and that will be significantly faster locally and probably even through VPN as I have a Gigabit pipe), Space (space on my NAS is cheap and only practically limited by my needs), reliability (even if my internet were to go down I still need to be able to keep my files synced incase I'd need to go somewhere on the fly), price (I already have all the hardware and for the amount of gigabytes and bandwidth I'd need I doubt that there's any free or cheap service). Those are my main reason for wanting to keep it locally.

I'm sorry for any spelling or grammatical mistakes that I've might have done. I'm writing this on my smartphone from a shaky train and English isn't my mother tongue. I gratefully appreciate any answers even if only partly solving my problem.