Magic Missile's upshot is that it ALWAYS hits, and actually does fair damage in the low-to-mid levels. Not a waste of a spell, but not great, either - but then, none of the direct damage spells are phenomenal.
Tenser's Floating Disk can be dispelled at will. Load up enough acid, alchemist's fire, holy water, or whathaveyou, and you can have a nice, arcanely-but-not-financially cheap explosion of LOADS of damage. Also, one will rarely prepare this until AFTER everything is dead, and it's time to take all the loot home. Or, occasionally, when everyone needs to get across the PIT OF DESPAIR.
Ventriloquism is a handy spell for superstitious monsters. Having the clan totem start shouting at them is nice. So is having their weapon begin to disparage them. But the best use of all is against creatures who aren't too fond of each other (like orcs). Combined with a good Bluff, you can start 'em knocking each other over. Better for Sorcerers than Wizards... Provided you aren't looking for a handier spell.
Charm Person's great. All it's good for is a temporary reprieve from the monster wailing on you... Or for telling that town guard to -trust- you... You OBVIOUSLY wouldn't have stolen anything in -his- town! You have far too much respect for him.
Or to get info out of someone... You get the idea.
