DD1: approx 4 hours
DD2: 47 mins (breech)
DD3: 13 mins (water ruptured spontaneously, and she started coming straight away)
DD4: 48 mins
DD5: 66 mins
DD6: 51½ hours (including 6 hours of excrutiating agony)
DD7: 90 mins (my perfect homebirth)
All the above are timed from first contraction until baby emerges. Add about half an hour to each to allow for delivery of the placenta as well.
With DD6, as soon as the water ruptured she came out in three contractions. It is my opinion that perhaps a manual rupture of the waters would've saved me a lot of pain.