There are dedicated Touring bikes in various flavours.
There are the Steel ones which supposedly provide some comfort and they are also supposed to last longer then an aluminium frame (if not crashed). They might have some corrosion issues.
The Aluminium ones, since Aluminium is 3 times weaker then steel, have 3 times thicker walled frames. So they might be a bit more crash-proof. They don't corrode as much. But they develop fatigue related cracks earlier then steel.
There is also Titanium...
For a touring bike you basically need a frame that has mudguards and rack fittings. You also need a geometry that is comfortable and the ability to load some panniers and such. Also touring-grade tires etc.
Some bikes to consider:
1. Surly Cross - Check. (Cyclocross Steel frame with fittings etc).
2. Specialized Tricross. (Cyclocross Aluminium frame with fittings etc).
3. There are many steel touring bikes, some brands to check are Trek, Fuji.
"Thorn" bikes are also very nice. They are custom made in the UK.
Since touring is mainly about reliability etc, you might want to avoid STI shifters and just go for a nice plain Bar-End shifting thing. These would cost about 5 euro each (maybe 10 if you get the "Dura Ace" ones [IMG]files.cyclingforums.combig smile.pngOpen ↗[/IMG]) which are very nicely priced to compared to the cheapest ones in the STI type which start at around 60 euro each for Shimano Claris non-repairable ones.
Good luck! [IMG]files.cyclingforums.comsmile.pngOpen ↗[/IMG]