Hi Iain -and welcome to the forum!
Some members of the forum have recently reported bad experience with Mavic rims on touring bikes, especially with the lighter models (they don't seem to be suited for an overall weight above 85 kgs). To be fair, their good service is also praised, but then again this won't help you if you're stuck in central Siberia because of a broken rim...
However, (assuming you are not using disc brakes), the EX721 still seems to be a reasonable choice for most purposes.
Rigida rims (X-plorer, Sputnik, DP2000) generally enjoy a good reputation among touring cyclists, as they are said to be stable, durable and rather inexpensive (which, of course, makes them quite heavy...).
When re-building your wheels, you should also consider using 36 rather than 32 spokes (if you are not already doing so) to enhance overall stability and reduce the risk of broken spokes.
Saddles: yees, they
are a very personal issue - ever tried Brooks Ltd., England
?
Greetings from Berlin
Bastian