I it all depends on how much is your budget. Some would prefer setting up a home file server or purchase a network attached storage device like
Drobo. Some would subscribe to
Picasa or
Flickr for their online backup storage for processed photos.
Me, I subscribed to Flickr Pro account. It's cheap ($25 USD) per year and reliable. I heard Picasa is much better because it retains the quality while Flickr seems to apply a certain post processing to your photos. It's like having your photos printed in your commercial photo printer and saying print "as is" or not. But Picasa is a bit expensive for me. I'm happy with Flickr and it saved me one time when my hard drive crashed.
As for my RAW files, I just put them into DVD if they reach 1 year old in my PC. I can't afford NAS solutions atm but I'm working towards that path.
1. All RAWs and processed photos into a NAS solution
2. All processed photos backed up online into my Flickr account.