Can you recommend wiki, forum, blog, and cms plugins for an existing Rails application, or do I need to follow the engines route?

I have an existing internal Rails application that handles inventory, billing, ordering, labeling, data import / export, etc. etc.

Now I need to add blog, cms, forum and wiki functions to it. It seems silly to try to deploy your own solutions when they are no longer there. So I was wondering if people could recommend, based on their experience:

• Are there any good plugins out there? (Which ones did you run into?)
• Would you rather go the engine route and integrate RadiantCMS or similar applications? (please provide recommendations based on your integration experience).
• Or do you just bite the bullet and unfold your own?

Thanks.

PS: Right now the app is Rails 2.3, but it will be updated to Rail 3 a year when most of the gems / plugins it depends on will be compatible with Rails 3.