My mother is not one with whom you would typically relate as a tech-savvy person. She would always complain to me when one of my portable hard disks would not show up on her computer or when she had to connect the same drive to every single laptop to view the pictures of my marriage.
Though she is not technical, her requirements are indeed ones that would give Bill Gates a run for his money. She asked me whether there is some way by which she does not have to bother about connecting the portable hard disks to each and every laptop because that was too laborious. In addition, not really understanding, how hard disks worked, she connected the hard disk to the laptop and wondered why these pictures won't show up on my Galaxy Tab or iPhone.
With more than 200 GB of data, I knew that SkyDrive and Dropbox were not the solutions for me, therefore I ended up buying the Western Digital Live. It is a cloud storage service for home where you connect the HDD to your router. The HDD obtains an IP address and you are able to connect to the NAS from device on the network. WD also provides with an application that enables you to view pictures or data from your HDD to your tablets or smartphones. Also, I am able to share my HDD as a URL link with anyone on the network to connect to it remotely. Of course, it is password protected so not anyone can read information off the drive. I connect to the NAS from my work and from the library over the WAN, and the connectivity is very decent.
I've been using Dropbox for about a year now and through referrals I have been able to keep ahead of my storage space requirements pretty easily. I believe it recently increased the total amount of free space you can earn to 18 GB. The Windows client and iPhone client works well, so unless I have a big incentive to try something different, I will probably stick with Dropbox.
Check what happens with your billing when you finally do exceed your limit on dropbox, and then let me know which is the better deal.