Lots of choices out there. You can tour on anything, but a properly designed bikes is a joy to ride. Raleigh, Fuji, Motobecane, Canondale, Bob Jackson, Dawes, Mercian, Trek, Miyata, Nishki, and Giant are ones that come to mind. Things to look for: braze on mounting points for racks, fenders and low riders (mid point on the front forks) triple chain rings (those won't always be on the older bikes) long cage rear derailleurs, long rear stays (look for the gap between the seat tube and the rear wheel) relaxed head and seat angles.
Aaron
