I bought a Nexus 10 (7's big brother) for my Netherlands tour last year. Best pre-trip investment I made. It's quite a bit heavier than the 7, but it was the only computing device I brought with me.

I'm surprised no one has mentioned my all-time favorite mapping app for Android: Locus Maps. The author is kind of a fanatic when it comes to fixing bugs and adding cool new features. It supports all kinds of bitmapped and vector offline formats, and online maps too. You can do cool stuff like snap a photo of a map, do a quick-and-dirty georeferencing, and then use it with GPS. When I first compared Locus and OSMAnd a couple of years ago, I felt Locus was the clear winner, although OSMAnd may have improved since then.

The other "killer app" IMO, are the free maps from openandromaps.org. They are OSM vector maps (which you can download and use offline) and themes which are customized for bicycling or hiking. They are available for most of the world, but especially nice in Europe. So in the Netherlands, for instance, you get a standard offline OSM map with the LF routes shown as dashed red lines and the entire node network shown as dashed blue lines, with all the node labels clearly marked. Indispensable! I imagine these should work with OSMAnd as well?

Re: navigation, I guess it works ok in the US. Going to Europe, I thought I had this all figured out. I wrote some Perl scripts to take the output of the very best online route planner (on the Dutch Cyclists' Union web site) and munge it into a GPX form I could import into Locus, complete with voice prompts so I wouldn't need the tablet out. Result: total fail! There is simply no way to capture all the subtleties of European road/trail intersections, routes are changing all the time, and even the best routing algorithms seem to "miss" some turns they deem too obvious to mention. If you are cycling principally on roads, maybe it could work; otherwise, I have resigned myself to periodically stopping and getting out the tablet. I can't see that changing until we have electronic paper displays with the size, resolution, and daylight readability of paper maps.