Well, it's interesting that most of those who posted say they prefer lightning bolt (for styllistic and/or role-playing reasons, even if fireball is far more likely to catch more opponents in its huge blast radius), while more than half who voted say they prefer fireball.
In my 20-something years of DM'ing, it's been my experience that almost every player prefers fireball; so much so, that I now house rule the fireball spell as either A.) being a level higher (i.e. 4th instead of 3rd), or B.) inflicts d4 per caster level instead of d6. (Then again, I've always made ample use of humanoid hordes, in my campaigns. So, of course a fireball in my campaigns can be quite effective.)