I have had to "switch" way too many sites from team to publishing. By "switch", I mean create a new one, transfer info, and delete old one. (grrrrr)
This tends to be the case with people that have switched from 2003 to 2007. Sure, you can create additional web part pages but when those open up expect your users to be a bit disoriented (not so good). What I usually see happening is someone creates a site and didn't imagine they would need more than one web page. Down the line, they "see the light" and realize their site could be so much more useful to both their team and visitors if they created more pages to serve up the content in their lists and libraries.
Here's one of my best practices related to this topic...
When you are assessing the information to be contained in a site and you've identified really valuable info that users can use often, create a new page to support that task. Use CQWPs, list and library views, etc. and "wrap" some helpful content around that using the content web part (i.e. "what do i need to know to use this information or further add to this information?", "what information is related?", "who do I contact for help related to this?", etc. - examples of "knowledge inputs"). I don't expect users to jump into a document library or list and just figure that all out and "get it right". Some power users and team members will be fine (though they might miss some important process points in your helpful content web part!) and that is cool but what about the "rest of us"!?
Amy Lisewski, MLIS
Sr. Enterprise Information Architect
Mixon Consulting