Well get an external HD big enough for your hard drives in use to be copied to, or if you have a CD-RW drive or DVD-R drive back it up to those. If you're using optical media it's usually best to use RW formats so you're not stuck with different versions of your hard drive and having to buy new discs constantly. If you go the external HD route or DVD-RW route, you can also use a backup script or program to back your hard drive up every night/week whatever. Otherwise you'll have to do it manually whenever you want to back up.
I have both an internal (13 gig) and an external (60 gig, 4 partitions), so i back my most important files up back and forth. That way if one fails, i'll have the most important stuff on the other one, too. i don't do full backup of both drives because it would just be wasteful, if i had a HD big enough to back both drives up to, i'd rather just use it for everyday stuff. There's not a lot of point to backing up programs that you have discs for, it's your files you should worry about.
i have internal 60 and external firewire 120 so im fine there, id like some sort of script or something that would automaticaly check for things that have changed since the last backup in terms of mainly files instead of programs. Is there anything like that? Also would I need to add a partition on my external hard drive? If so how would I go about that?
You wouldn't have to partition, really anymore it's just a convenience thing. And it can become inconvenient in a hurry if you're not careful... If you want to, you'll have to reformat the entire drive that you're partitioning. Not light work, in any case...
I think Carbon Copy Cloner will create timed scripts for you if you want... It's by far the best duplication software; it copies *everything* pretty much perfectly. Check versiontracker for it. Not the easiest program to use but it's not bad either.