http://www.jottacloud.com/ - Norwegian company. I don't know whether or not they have servers in the US, but you could always ask.

Edit: Their FAQ (http://www.jottacloud.com/faq/) says data is stored in Norway. Which AFAIK is better than the US in terms of privacy.

http://www.wuala.com/ - Swiss company. 5GB free storage for client-side encrypted data. The product offers backup and sync options for arbitrary folders and is supported across OSX, Linux, Windows, and Mobile. Backed by a big company (Lacie) who make USB drives. I have just switched to them from DB and have loved the experience so far.

https://www.tarsnap.com/ usually comes up when talking about Dropbox alternatives, I have not used Tarsnap myself but I've seen many who have been pleased with it.

I am not sure if there are any big Dropbox competitors operating from outside the US (if NSA is your concern). There should be but I am not aware of any.

I use tarsnap and like it but it really isn't a dropbox alternative.

If you want client side encryption with close to dropbox functionality use spideroak, if you want snapshot/dedupped/backup + encryption use tarsnap.

Hmm, yes you are right.

Spideroak's functionality seems closer to Dropbox. Spideroak does seem more practical to use.

http://git-annex.branchable.com/assistant/ is still in active development. It is not exactly a Dropbox analogue, however it can easily fulfill the role of a synchronization agent with a cloud service (S3, Glacier, or similar).

It supports strong encryption.

I've got encfs running on both MacOSX amd Linux, storing encrypted partitions on Dropbox, gDrive and BTSync.

What that isn't giving me yet is Dropbox style iOS integration. (though there's a promising looking BoxCryptor iOS app,mi haven't made time to test it yet)

https://mega.co.nz/ ?