Lackhand said:
If you're willing, do you get a saving throw against whatever the effect might be?
Signs point to no.
There's a difference between "Willing creature" and "creature foregoing saving throw".
Most spells that affect "One willing creature" or whatever permit no saving throw.
I can be a willing creature, yet still roll Will saves to which I am entitled.
An unconscious creature is a valid target for Levitate (target: one willing creature), but he will still get to make a Will save against Inflict Light Wounds. Indeed, he must; in order to forego his save, he must elect to do so, and while unconscious, he isn't making any decisions.
The exception is Harmless spells, where you can choose to
make a saving throw (if one is permitted), but the default is that you do not. So a conscious person can elect to make a saving throw against, say, Darkvision; but if they are unconscious, they cannot make that decision, and so the spell takes effect.
Regarding fireball in particular, and Reflex saves in general, I hold that an unconscious creature cannot make them; an unconscious creature is helpless, with an effective Dex of 0, and is therefore considered paralyzed, and cannot move.
Per the text of Evasion, a creature must have room to move in order to make a Reflex save.
And if a creature cannot move, then no amount of room is sufficient 'room to move', prohibiting Reflex saves.
This is not a universally held position, however
-Hyp.