I'm looking to use a NoSQL solution for my next project, which will be written in PHP. What choices do I have in terms of NoSQL solutions that can easily interfaced via PHP? I haven't done much thinking about the architecture yet, so I'm not sure what my needs will be; I'd simply like to know what my choices are so I don't build something I can't reasonably implement.
For instance, I know Cassandra has Pandra, but that's just a PHP library. MongoDB has a native PECL extension.