Time machine and file storage?

Hi

I am new to the Mac OS world and I am just trying to learn a few things.

I want to use a 500 giga external drive to backup my macbook pro 350 giga harddrive. But as I will not need to backup movies files and so forth I will probably be no where near using all the 500 gigs, not even with multiple delta backups each day.

So the question is will using a harddrive with time machine make it a dedicated backup harddrive or can I still use it for files an other things that I copy myself?

 

Thank you that seems to be the way to go.

What file system should I use for the TM partition?