Just a quick note: I have learned through sad experience that I can expect to lose all of my files at least once a year. It WILL happen to you too. Don't be optimistic, be smart. Backup all of your files.
I like to keep my family history on a Flashdrive. So far I haven't used up the 2 gigs of space. This allows me to take it anywhere I want.
The bad news is that a flashdrive is very easy to lose. So I also keep a copy of my family history folder on my computer. Once a week I delete the old one on the hard drive and transfer a new copy from my flashdrive, so I would lose a week's work at most if I lost my flashdrive.
I also recently purchased a portable hard drive for about $90. It is about the size of a hardback novel and holds 250 gigs of files. Every few weeks I'll copy my family history folder there as well, in case my computer crashes.
This may sound a little neurotic, but it will save your bacon. At least have two copies of the folder. Just remember to not start doing research in your backup folder, since then you'll have two different versions of your work.