nameless said:Telekinesis can do 15d6 with no save if you hurl a dense, heavy object, like a boulder. And unlike Scorching Ray, it allows no SR, no DR, and no energy resistances (which apply triple to Scorching Ray).
Acid Fog will do 2d6 acid damage (no save) per round, and Cloudkill will do 1d4 Con damage per round (Fort half). Put up a hemispherical wall of ice (creatures not adjacent to the wall aren't given a save) over it, and the bad guy is trapped in there with the damaging fog until the duration expires, or it breaks the wall.
Enkhidu said:If you're talking a long combat, the spell you're looking for might actually be Mordy's Sword (or Mage's Sword in the SRD).
SeRiAlExPeRiMeNtS said:If the maximum spell level is 7 the best you can do is a maximized enpowered scorching ray, witch deals 72 + (12d6)/2 = 93 points of fire damage on average.