[Suggest me] File download directory plugin.

Hi guys!

I am wondering if you can help me suggest a suitable plug for my blog. I am looking for something like this:

1. We setup a filedirectory. Can look any way as long as we can modify it.

2. The filedirectory will hold a bunch of files, mainly pdfs/word documents, in different categories – category1, 2 etc.

3. Then we will use something like “wordpress like gate” to make the users like our page before getting access to the downloads.

4. The plug needs to be easy to maintain, ie we just upload a bunch of files and it works.

5. I would love to have some comment/syllabus function where we write a small summary about the file. F.ex “this is an interesting book about three small bears” ??

Thank you for all suggestions!