After killing the Uldred abomination and getting the Templar's promise to aid in battle against the Blight, return immediately to the Harrowing room at the top of the tower. The Uldred Abomination may appear again (without minions) in the PS3/Xbox 360 version. When you kill him the second time, you will get the same experience and items once more.
This also occurs in the PC version, at least with version 1.02. In the PC version, though, he respawns each time the Warden enters the Harrowing Chamber, but doesn't carry any items. You only get the experience for killing him again.