How to keep cloud data encrypted without cross-platform pain?

bromoseltzer writes: I use cloud storage to hold many gigs of personal files that I'd just as soon were not targets for casual data mining. (Google: I'm thinking of you.) I want to access them from Linux, Windows, and Android devices. I have been using encfs, which does the job for Linux fairly well (despite some well known issues), but Windows and Android don't seem to have working clients. I really want to map a file system of encrypted files and encrypted names to a local unencrypted filesystem — the way encfs works. What solutions do Slashdot readers recommend?

Ideal would be a competitive cloud storage service like Dropbox or Google Drive that provides trustworthy encryption with suitable clients. Is there anything like that?