I use a tool called pwqgen:

nux@stone:~$ pwqgen random=81
Under8Aroma-levy7boyish3Tutor
brass5cork!Trim=Warmth=Cycle
Rudder+colon$Dense2radio$Guilty
Tariff2Maybe7Bark7ribbon2wipe
Warp9noun_Dove-Tweed*Gang

You can even get somewhat readable/memorizeable passwords if you want

nux@stone:~$ pwqgen
Nicely+French&Viola