To go back to the auto/manual brakes issue...
I assume that just after touch down, speed brakes and reverse are going to perform most of the braking (especially on a contaminated surface). So fundamentally, whether the brakes are applied immediately by the autobrake system or whether there is a slight delay because of human hesitation in case of manual braking, the stopping distance won't vary THAT much. However... Since the important thing would be to apply reverse ASAP, I would chose to have as little distraction as possible (i.e. should I jump on the brakes now?) and leave it to the autobrakes, so that I don't mess up engaging reverse by doing so too early (or when the thrust levers have not been retarded all the way back) and ending up fighting the levers.
If indeed, as per NTSB report quoted earlier in this thread, max manual braking gives a slightly shorter stopping distance than max autobrakes, then the pilot can jump on its brakes (thus cancelling autobraking) once reverse is engaged. Sounds to me like this operating procedure would offer the least risk of messing up engaging reverse, while producing maximum wheel braking effectiveness. No?
BTW, I'm just fresh out of ATPL school (hence the alias), so I could be talking crap :-)
P