My Proposed Nightwalker Second Job Build

Joe proved using Sudden Attack before every attack increases DPS by 1%.

Increases chance of death by 400% at the big bosses

Here's the skill build I have in my guide:
• 1 Flash Jump, 1 Sudden Attack, 1 Vampire
• 5 Claw Mastery, 6 Booster
• 30 Critical Throw (max)
• 19 Vampire (max)
• 15 Mastery (max)
• 9 Sudden Attack (max)
• 19 Haste (max)
• 14 Booster (max) OR some mix of Booster and Flash Jump
You only end up with 1 FJ, unfortunately. Vampire is an awesome skill, you don't want to be missing out on a whole hunk of damage for not maxing Mastery. Crit is pretty much a neccesity for raising Vampire though, it raises the average damage of Vampire from 30% per hit to 80%.

If you need ideas for 3rd job, you can PM for a link to my enormous guide on all things cygnus, but I don't want to be busted for advertizing a link here.

What's BETTER to do is max everything except 11 booster, and 0 sudden attack.
Wait til lvl90, and take out the sp you plan on putting into avenger, and max out sudden attack with it (because you'll end up with 21 avenger, 0 shadow meso, and maxed everything else in 3rd job with this build).