Cloud Service

dropbox

you can also put it on your phone and it will automatically upload any pictures you take

Google Drive for photos. Anything under 2048x2048 is "free" on your storage limit. I also store documents on it, and most things I need as a backup. Apparently any videos sub-15 minutes are free as of last year.

I use dropbox for very small files, backups of text documents and such.

I back up larger files to mediafire, have a full save backup (mydocs/mygames/) as well as any files I need to share.

For backing up video, I upload it as a private video to youtube. However, if I need a proper source for editing later, google drive it.

Cloud storage services are pretty even these days, although some are move even than others :)
People tend to choose the one from which they can get the most free storage through promotions, referrals, etc.

A quick comparison can be found here:
http://time.com/25107/chart-cloud-storage-services-compared/
A more detailed one here:
http://www.pcadvisor.co.uk/features/internet/3506734/best-cloud-storage-services-review/

If your problem is lack of hd space, then cloud storage is not the solution. I recommend getting an additional HD. Even a USB HD might be fine.

A few problems:

• Your internet upload speed is probably too slow. If your stated upload speed is 2 mbps, then it could take between 1 and 2 hours just to upload 1 GB.
• By default, the most common way cloud storage services are used, they keep local copies of all your data anyway. So you won't save any space unless your decide to micromanage how you store things.
• I wouldn't recommend having the only copy of your data on the cloud, specially just one service. You might not be able to connect when you need it. They might lose the data. Etc. That's why they usually default to keeping local copies on your hd. Of course, keeping the only copy of your data on your hd isn't entirely safe either, but for better or worse, at least that's mostly under your control.
• You'll probably need more space than what you get for free. Then you'll have to pay a monthly fee forever, or at least until you no longer need it. Considering how cheap HDs are. It won't take more than a few months for the cloud storage to surpass the HD in cost.

Cloud storage is useful whenever you need to access data from different places. Otherwise it's quite expensive, since bandwidth costs a lot more than disk space.

I just use it to backup files from my phone (pictures) and a few other things but my use is very limited due to my insignificant upload bandwith