I've run my OS X machines from a non-admin user for at least 5 years. I do developer-y type stuff like SSHing into Linux servers with key authentication, running a local web development environment (MAMP), installing brew applications from the command line, editing my /etc/hosts file, etc.

It all works fine. For most things, like software installs and updates, I just get prompted for admin account credentials. For a few things (brew and editing hosts file), I su to my admin account in Terminal, then run the command.

I can't remember the last time I actually logged into my admin account, though.