Several Content Types

I need to create several different types of content for different members to be able to submit.

1) Announcements: for site administrators to create, the headlines of which will display in a left sidebar.
2) Discussion Topics: for general users to create, to be displayed on the main page - eight categories. (Side issue - the front page should display the top 1 article of each of the discussion categories. Not sure how to accomplish this yet.)
3) Resources: If someone is reading the "Hardware" topic, they should be able to submit to the "Hardware" Resource listing - like a link or a tip/note, the headline of which will show up in the right sidebar of that discussion topic page, but would not be on the main page for that discussion topic itself.

Now, perhaps because of my inexperience, it seems the best way to do this is to install flexinode and have each be its own node type. Is that right? Or is there a snazzy way to do this all with just "story" or "forum", using the out-of-the-box taxonomy module? I don't want normal users to be able to create Announcements.

I suppose I could have "announcement" be the sole category for "stories", and have the rest be done through "forums", using two separate taxonomies? I would just prefer to control it so that if someone chose a discussion topic, they couldn't also choose a resource topic. It'd have to be one or the other. As you can see I'm having a little trouble wrapping my head around this.

Thanks!