Netherwalk/desperate instincts depending on comb.
Momentum/nemesis. (I play nemesis in 90% of games). This choice also relies on what comb you play.
Master of the glaive. You could play unleashed power for shorter stun CD, if you play with a class that has a slow. Although you lose DMG for not having 2 glaives.
I only play chaos blades. Chaos blades sync so well with 2 min metamorphosis. I always pop these at the same time. I see some people playing fel barrage but I feel Chaos blades + demon form works waaaay better, since you do unhealable damage to druid with double skin up for example. (You kill anything, if you have uptime through their defensives).