Here is a post I posted somewhere else recently:
A couple months ago, I would have recommended the Marathon XR, but Schwalbe discontinued it. So you might find a few stores that still carry it, but I guess it won't be for very long.
However, the models replacing it seem even better (new technology, design, etc.).
According to what you're saying, I would suggest:One of the Schwalbe Plus Series
: If you really want the toughest and most puncture-proof tires, then I suggest the Marathon Plus or the Marathon Plus Tour. They offer the best puncture protection of all the Schwalbe tires. The Plus Tour is better for off-road than the Plus.
or, One of the Evotion series
: These still have good puncture protection and will also last a long time. Although not as good and not as durable as the Plus series, the tire is much lighter and also faster. The Supreme is the fastest, but least durable, in this series. So you might prefer the Dureme or the Extreme (these are technically the replacement for the Marathon XR). Out of these 2, the Extreme is better off-road (and 65 grams heavier).
You certainly can use a different tire on the back. A good idea could be to use a more durable Plus model on the back and an Evolution tire on the front. Also, note that the Evolution series, having the "best" touring tires from Schwalbe, also have the most expensive touring tires.
I haven't updated this page for the new 2010 models (I'll do it in the next week or so), but you can easily see the different specs and easily compare all the Schwalbe tires on this page:Schwalbe Tires for touring
Note: All of these tires are now folding tires.