They should drop a present with wrapping paper selected from a small collection. Each kind of wrapping paper has a different effect in each world, but has the same effect as other presents with the same wrapping paper. Some of these effects will be very bad. You have to open the presents to find out what each wrapping paper type does.
One type of present randomizes the results of all the presents, so you have to start again.
Pumpkin seeds? Though Notch said pumpkins would be useless as helmets, so unless carving jack-o-lanterns actually has some practical use, (scaring away enemies?) it seems like a kind of poor reward for killing the hardest enemies in the game so far. Maybe it could drop something used in making the watch, though that wouldn't make a whole lot of sense, and we don't need ANOTHER enemy that drops something that eventually becomes virtually useless. (I'm looking at you, :Spider:.)
and if you manage to collect enough you make a chapter, and after you combine enough chapters you make a necronomicon which when used has a random affect maybe? potentailly spawns a n army of skeletons or a couple of ghast, maybe instantly heals you or sets the nerest mob on fire!
Reading from the Necronomicon (After speaking Klatu- Verata- Ni- What was the third word again?) should spawn Bruce Campbell. Whisk him right away from the Burn Notice set into the game.
How about fire blocks? There was a plan to use fire blocks for making chainmail armor, and the armor is still in the game so this could be Notch's way of re-adding it. It would be pretty cool thing to have, and be still used as a projectile. This would give a good reward and reason for killing gasts.
There wasn't a plan to use fire "blocks" to craft chainmail, you just weirdly can for some reason if you hack them in. (They don't come in a block form, when you're crafting with them you're literally just combining a bunch of fire together, so I doubt it was intentional.) Perhaps Notch was working on some sort of material that would have been used to make chainmail armor, but gave up partway through and gave fire that spot in the game's data instead, but left the recipe in on accident. In any case if chainmail ever is made so you can get it in-game without hacking, the recipe is unlikely to still involve fire. Do we really need chainmail, though? It seems kind of unnecessary, if you ask me.
I think ghasts should drop a material that can be crafted into flame resistant armor, that would make lava, fire, and explosions do less damage (maybe full protection if you have a full undamaged set of armor?) along with iron armor's level of durability
They should have a quite small chance of dropping a tentacle, these tentacles could work with the bow schematic but instead of string... The tentacles.
This would produce a bow that shoots fire arrows, however the arrows have a 10% chance of dissipating in mid air (Burning to ashes in mid air?) or the fire going out and just being a normal arrow.
Tentancles? I pity the the japanese schoolgirls who play minecraft. Ghast shouldnt drop book pages because how do we know that the minecraft guy can read? He never uses his bookcases! I do agree with the fire ball idea, maybe you could add them to arrows to get fire arrows.