The Collaborative International Dictionary of English v.0.48:

Consequential \Con`se*quen"tial\, a.
   1. Following as a consequence, result, or logical inference;
      consequent.
      [1913 Webster]

            All that is revealed in Scripture has a
            consequential necessity of being believed . . .
            because it is of divine authority.    --Locke.
      [1913 Webster]

            These kind of arguments . . . are highly
            consequential and concludent to my purpose. --Sir M.
                                                  Hale.
      [1913 Webster]

   2. Assuming or exhibiting an air of consequence; pretending
      to importance; pompous; self-important; as, a
      consequential man. See Consequence, n., 4.
      [1913 Webster]

            His stately and consequential pace.   --Sir W.
                                                  Scott.
      [1913 Webster]

   Consequential damage (Law)
      (a) Damage so remote as not to be actionable
      (b) Damage which although remote is actionable.
      (c) Actionable damage, but not following as an immediate
          result of an act.
          [1913 Webster]

WordNet (r) 3.0 (2006):

consequential
    adj 1: having important issues or results; "the year's only
           really consequential legislation"; "an eventful decision"
           [syn: consequential, eventful]

Moby Thesaurus II by Grady Ward, 1.0:

130 Moby Thesaurus words for "consequential":
   absolute, ascendant, authoritarian, authoritative, authorized,
   autocratic, big, big-league, big-name, big-time, bigwig, bigwigged,
   charismatic, charming, clothed with authority, commanding,
   competent, complacent, comprehensive, consequent, considerable,
   conspicuous, controlling, deep, derivational, derivative, dominant,
   double-barreled, duly constituted, earthshaking, effective,
   effectual, efficacious, eminent, empowered, enchanting, ensuing,
   estimable, ex officio, exhaustive, final, following, full,
   governing, grand, grave, great, heavy, heavyweight, hegemonic,
   hegemonistic, high-powered, imperative, important,
   in the limelight, influential, intense, irresistible, leading,
   magnetic, main, major, material, maximum, meaningful, mighty,
   momentous, monocratic, name, narcissan, narcissine, narcissistic,
   narcistic, official, outstanding, overproud, overweening,
   personable, persuasive, plenary, potent, powerful, preeminent,
   prestigious, prominent, puissant, ranking, reputable, resultant,
   resulting, ruling, self-admiring, self-approving, self-assuming,
   self-complacent, self-congratulating, self-congratulatory,
   self-content, self-contented, self-delighting, self-endeared,
   self-esteeming, self-gratulating, self-gratulatory, self-important,
   self-loving, self-respecting, self-satisfied, self-sufficient,
   senior, sequacious, sequent, sequential, serious, significant,
   smug, strong, suasive, substantial, superior, supreme, telling,
   to the front, total, totalitarian, vain, vainglorious, weighty,
   winning, world-shaking