Ask HN: Building a community

I am in the process of moving my existing site into a more community driven site. This would include profiles, commenting, discussions, etc. In the past I have used Drupal for these sort of things, but I don't think it is the best solution for my site because I have a lot of JS activity and hate Drupals implementation of doing AJAX and JS. Drupal doesn't really look all that great either and I am not a themer.

With that said, I don't know what to go with. Framework or no framework? I know PHP, but it seems like it would be more than it was worth to build my own community system from scratch. I could use a PHP framework, but there are so many and I am just not sure what to go with (if any). And then there is rails which seems to have the biggest appeal. I have a buddy who knows rails, but I am new to it.

I understand I will have to put in work regardless of which way I go, but has anyone had experience building and maintaining a community site? What did you use and why?