I have over 600MB of photos in my computer back home. And I am backing them up on a Time Capsule and on an extern drive. Total: 1.8TB.
More than that, in 13 years I have seen an increasing storage need that has been following the Moore's law. It is because I am taking more photos, but also because I have changed the cameras over time and what required 300KB for a digital photo 13 years ago (I had a point and shoot Nikon with 1.3Mpixel) now requires 10 MB per photo (I have now a Nikon D600 with 24Mpixels - and yes I know, it is an old model but replacing it with a new one would require some lengthily discussion with my wife...).
Storage cost kept decreasing. The last 3TB hard drive cost me less than 100$.
Now I read that Amazon has launched an all you can eat (you can store as many photos as you like, no limit) for 11.99$ per year. Now this is what I call a great offer.
No more backup headache at a price that is lower than the one I would have to pay to keep my photos "in house".
For the time being I will be using Amazon service only as back up but if it works as nicely as they say I will be moving all photos to the(ir) Cloud.
Of course you can access your photos in the cloud from your computers, your tablets and your mobile devices. Provided the connectivity is good you'll feel you have all your photos always with you.
A pity we don't have a similar service in Europe....