Acrobat is really an obvious choice for a perk line that should be maxed. Besides raising all evades by 190, agility by 30 and multi-ranged/multi-melee by 30, it adds two fantastic perk actions.

Limber, which can be gotten as early as lvl 60, adds 200 to all evades and can be used every minute and 5 secs. It lasts for 40 seconds.

Dance of Fools can be acquired as early as level 140 and adds an insane +800 to all evades. It also can be used every minute and 5 seconds and lasts for 40 seconds.

Edit: (01.17.04) As of a few patches ago, Limber and Dance of Fools actually stack with each other for a total of +1,000 to all evades.