vanil and lif are my favorites. Vanils for thier power and versatility, Lifs for emergency avoid, the speed kicks so much ass

A vanil with high magic attack is great in pvp/WoE because you can put the caprice skill on your hotkeys, and have a clickable ranged, powerful magic attack.
Being able to move at ultra fast speeds with lif has many advantages: Running away from mvp's in between acid demos, running away from opponents in pvp, giving you time to heal up, and getting through a castle at top speeds in WoE. Those are just a few that come to mind, there is probably other good uses.