backup to another drive and/or to the 'cloud'
I have google/picasa account so now pay for space (its cheap) and sync the full size picasa albums between pc and cloud.
I do only store 1600 px size on web but you can select full size if your upload speed is sufficient.
If the house burnt down (god forbid) I would only have the 1600px versions left online
you can also use dropbox or a.n.other cloud storage solution. depends how many photos, whats the MP count. raw vs jpeg is quite a storage difference