The worst game is Knights of the Old Republic, followed by KOTOR II.
May I ask why?
This is how KOTOR generally goes:
Sweet a star wars RPG, and its made by the Baldur's Gate guys...this oughta be good...
(HOURS OF USELESS AND INCREASINGLY MORE BORING DIALOGUE COUPLED WITH...)
Oh sweet, I want to attack that guy (PAUSE!) Oh shit, now I have to do the most boring shit ever...but now I'm ready to battle (UNPAUSE!) Sweet, okay, I'm attacking...ON NO WAIT, Fuck, thats not what I wanted him to do (PAUSE!) Okay...yeah...okay....maybe this is it...(UNPAUSE!) What the fuck are you doing Jedi man?!?! FUCK! Kill that dude! SHIT FUCK DAMN ASS FUCK!
(THROW X-BOX OUT WINDOW, no easy task mind you)
(BUY FFX, SMT:Nocturne, Ratchet and Clank or something that is actually quite playable and doesn't make your soul want to die)