Clickable continent/country maps: which way to go?

Well it is not really a problem which could be tagged 'geocoding'.

Since I have been playing with Raphael.js these days, I thought of this lib while reading your question title. I also remember Wikipedia commons hosted a SVG map of the world. Raphael helps you manipulate svg files, so that could be a nice way to go. Anyway, after searching whith the criteria 'raphael' I found a conversation matching your request, exactly. So there it is : http://groups.google.com/group/raphaeljs/browse_thread/thread/46b5402c677ce274/7ff6a6a8d8f5f9fa?pli=1

There are some utility scripts, as well as the link to the svg world file mentioned above and a live examples (and links to Stack Exchange topics).
Sure there is work to do, and it may be easier to call directly the google api.

In my experience of the gmaps API, you have to make many requests per second to be blacklisted by google. Like when you launch a heavy batch geocoding tool. So it depends of your project but I would consider quite safe to use it even if your page is popular.

[EDIT] : There is now a live demo on RaphaelJs website.

[EDIT again]: And now a complete production workflow based on Python and Raphael exists : Kartograph. It's really young but looks promising.

Check this out. Seems to serve your requirements and offers a bit more:Google Maps with Clickable Regionshttp://codecanyon.net/item/google-maps-with-clickable-countries/3186942

I second the raphael.js, it is a nice library to draw the shapes with all kinds of user interaction. As an example, you may look at this project, which is a vector map of Russia, implemented on top of the Raphael.js. It allows highlighting the regions programmatically.