I'll put in another vote for the VDO MC1.0 (the wired version). I've used it for 3 years and ~10,000 miles and haven't had a single problem with it. On top of that, it's awesome, it does exactly what I want it to do. The only con I would give it is that it doesn't have a backlight like my old Specialized one did. But overall I like the VDO more than the Specialized (which also had altimeter/grade functions). Since the altimeter is based on air pressure, it will vary with the weather, but in terms of of relative altitude within a day's ride it's remarkably accurate (correlated with DeLorme Topo altitudes and GPS readings)
I don't think I'd be able to do a tour without altimeter/grade functions, I've basically become addicted to tracking that information. So I love my VDO, it's one of my favorite pieces of cycling equipment.
Neil