Packages And Styles
Packages
In the early to mid 1990s MS-Word was 'just' a Word Processing package. Any serious professional authoring really did require the use of more 'professional' packages such as Pagemaker or Framemaker - both now from Adobe. Since the late 1990s MS-Word has developed to such an extent that it has all the features I need. It is true that MS-Word 'misbehaves' as its documents get longer, but I rarely find the need for my documents to be longer than 100 pages - even though I've been 'required' to create some with almost 300 pages.

However - I've been using MS-Word exclusively since 2000 and not felt the need to use anything more 'professional' - it does what I need it to do.
Styles
In keeping with Freedman's Seven Sins I believe the same sort of things are true about the look and feel of technical documents. I don't try to create 'cool' or 'flashy' documents, I think about the people who will be using my documents to do something and create simple styles that make it easy for someone to find what they need.

Fancy headers and footers with the company logo in them don't make a document easier to use - page numbers, coloured headings and indented paragraphs do.
Simple Template (example)
When it comes to creating a template in MS-Word I keep it simple. I modify the built-in styles starting with 'Normal' and 'Heading 4' adding colour and increasing the font-size and paragraph spacing as I work up to 'Heading 1'. By choice I don't use numbered headings or illustration captions - look at any modern computer book, they often don't either (because they clutter the page without helping the reader).

A sample document (94Kb) - based on a simple template.
The Future
That said - I don't think MS-Word documents converted into pdfs are they way of the future. Who really wants to flick through a multi-page document (even on-screen) to find a single paragraph or line? Not me!

I think Google, Online Help, and WikiMedia have shown the way. It seems obvious to me that documentation must move into the searchable, hypertext space. When I need to know something - I usually reach for Google or Wikipedia - not a book. With an internal WikiMedia solution anyone in a company can create, read and update any article in the knowledge base and - if needed - emailed it to anyone in the world.