Gilded Lotus is fun to chuck to Thirst For Knowledge, and then Trash For Treasure out of the 'yard.
Also, I've seen people dump Duplicant, and then Trash (or Welder) it out as a good way to remove your opponent's creatures.
LordLamneth
Since I play Standard right now I only got 4 "welds", Trash for Treasure, and thus I don't want to spare any of them for just mana, Gilded Lotus. As for Duplicant it would be great as removal over and over again, but it's the same thing there - it would be great with Welders, not so great with Trash...