Long Distance Navigation I'm looking for what's available in terms of navigation for long distance rides.

I will hopefully be doing some cycling around Europe in the coming summer, and would like to be able to know that I'm not going to get lost.

I'm open to all solutions, be it GPS navigation or strapping a map and compass to my handlebars!

What are the pros and cons of my options and what is most workable?
I spent all last summer biking around Ireland, France, Italy (a bit), and Germany with my wife.  We went with map and compass to avoid being dependent on a battery to not get lost.  

Map Scale.  In general, you need at least 1:250k map scale in my opinion.  More detailed (i.e., 1:200k or less) is nice, but you can end up buying/schlepping a lot of maps that way.  

Ireland. We used a 1:350k Rough Guide map that was just not quite detailed enough for bike touring. 

France. Go with Michelin 1:250k regional maps -- super accurate.  

Swizerland. Use the SwissTrails pdfs (a tour operator, but they are good), and follow the signs.  Most amazing signage in Europe. 

Germany. The ADFC/BVA bike maps. Also has crazy lots of signs, but the map really helps.

Italy.  We used Michelin again but were disappointed in the accuracy, particularly compared to Michelin's France maps -- never found a good alternative though (we left Italy after a week since it was just too hot to tour in July).  

Map Holders.  See "Map During Touring?" on this site for info on map holders.  

Compass.  Definitely strap a mini-compass to your handlebars.  Invaluable.

Camera.  I didn't really think of a camera as a navigation device before this last trip, but it is really useful to take pictures of maps. Many European towns have maps posted on the outskirts, and it can be helpful to take a picture to refer to later.  We would have been lost in a park in Italy had we not taken a picture of the trail map on the way in. Similarly, you can save on printing costs at an internet cafe by taking pictures of Google Maps at various zoom levels. I wouldn't plan a whole trip based on camera maps, but it is really nice to supplement.  Just make sure you have extra batteries, that you know how to use the pan and zoom on your camera, so you can look at the details of a map-picture.