Quickdraw is one of those feats that makes sense for some characters but not others.
I play a fighter 2/wizard 6 who uses quickdraw all the time. His main weapon is a glaive which he uses to take AoOs on humanoid foes as they charge him. At that point, he drops the glaive (free action), draws his light flail (free action because he has quickdraw), readies his shield (move equivalent action), and can still attack. This is also useful for allowing a weapon switch as he moves. He can drop the glaive, ready the shield (combined with his movement), quickdraw his weapon, and attack. The ability to switch to his shield and single handed weapon only in the round in which he wants to attack enables him to minimize arcane spell failure by not having his shield readied when he casts spells.
It is also useful if a DM insists that he needs to spend an MEA to ready his glaive after letting go with one hand in order to cast a spell. Some DMs have also let me use the feat to grab wands or scrolls as a free action.
In theory my character could also charge one foe, drop him with an attack, cleave into another, and drop the second foe too. At this point, only having a haste action left, he could drop his weapon, quickdraw his bow and ready an attack to disrupt any spell cast by the opposition.
I've also found it useful when my character has been hit by Confusion. If combat is over, as soon as he rolls to act normally, he quickdraws and drops all of his weapons so that he isn't a threat to other party members.
Other characters who find quickdraw useful have already been mentioned. Anyone who gets into combat a lot without having already drawn their weapons. Anyone who uses thrown missile weapons. Anyone who wants to regularly switch between weapons.
