Hi Nick,
during the skull strip stage, an alignment to an atlas is computed, which takes quite a bit of time (40-60 minutes).
Just so you know, this isn't included in the approximate timings in the help for recon-all, which seem to suggest that autorecon1 should be more like 15 minutes in total: -<no>motioncor < 5 min -<no>nuintensitycor 3 min -<no>talairach 4 min -<no>normalization 3 min -<no>skullstrip 1 min
Cheers, Ged