is use the free version of syncback http://www.2brightsparks.com/ to backup everything to an external HD.

Also I use Picasa 3 to view my photos, it has the feature to backup your photos to CD or DVd and remembers what has been backed up.
I TRY to backup my pics when I add them but its not always up to date.

Online storage is a good idea but can be expensive, Picasa 3 offers a small amount of FREE on line stoarge, that can be upgraded if needed.

Gav