What's the best place to back up my pictures online?

I’d like to backup all my pictures to the cloud, in a way that makes them easy to re-download in bulk later on.

Requirements:
* Easily upload pictures to a private location
* Easily re-download all pictures to my drive

I have Flickr Pro, so I’m debating using that, but I’m not sure how easy it would be to re-download the shots.

Any other suggestions?

Thanks,

-Nick