they should drop a reagent that you can add to milk to make cheese. and to all those "Notch hasn't even killed one yet!?..." THat was over two weeks ago, just because he didnt tweet "hey I finally killed one" doesn't mean he never did, lets try and use our reason here.
They shouldn't drop anything, they should explode into water, thus putting out nearby lava. Alternatively, they could explode into lava, so just when you think "I KILLED A GHAST OMG!!" It has also killed you.
Rollback Post to RevisionRollBack
If you are reading this, I want you to know...
You just wasted .0000000000000000000000000000000000000000000001% of your life. }=D
Reading through here I like the idea of Ghast tears, however I believe they should serve a different function. I think they should work to prevent the spawning of Ghasts in a certain area.
Example: As has been stated, you can build a base in "The Slip/The Core/Hell". There is one caveat to this, you cannot build big rooms without risking the spawning of Ghasts, why not have the tears combine with a lit fire to create a "fog" in a room which prevents the spawning of Ghasts there.
I like it because it forces people to interact with Ghasts in order to assure they don't end up with the in their houses.
since notch said Ghast are nearly impossible to take down with sword i could see us getting a new weapon.
maybe the stuff that doesn't stop burning might be crafted with sticks to create a fire staff that uses slimeballs (baby slimes) to operate. i say baby slimes because it sounds evil and it's the core were talking about.