pick your brain - platform for an e-mail newsletter?

So I'm researching a platform for a newsletter.  And I'm hoping that someone will have an idea about the tool we need.

Requirements:

• Be able to auto generate an e-mail with the newsletter contents from a list of subscribers that we input.
• Web front-end to aggregate past newsletters and search content.
• Ability for readers to comment on individual newsletter stories from Website.
• Readers can self-subscribe to receive the e-mail newsletter.
• RSS feed.

Some Questions:

• We think we want the format of the e-mailed newsletter to be a pdf.   This would give a nice document that can be printed or read on screen.   Thoughts?
• I think we are looking for something that combines a static website (with new pdf newsletters added and aggregated) and a blog (with RSS feeds, commenting and searching within the content).  Is this really what we we want?
• The thought is that the newsletter would be authored offline (say in Acrobat Pro or Word) and then uploaded to the site/platform - which would automatically send the newsletter to subscribers by e-mail as an attachment.  Is this really what we want to do?

Seems to me as I write this that all these things could be done manually....by say starting a blog and uploading the newsletters - and then manually e-mailing out the newsletters.  Doing this on a blog would allow commenting - and for people to discover the newsletter etc. who were not on our mailing list (or opt to consume it online).   What am I missing?  Is there a tool that does this all?  Does Typepad have this tool?  Or do we want something else?