Who are some characters that you think had the best voice actors? Who are some that you think had the worst?
I gotta say G-Man from the Half Life series is one of the best. The weird inflections and audible inhales are top notch.
One of the worst, which is mostly due to script writing, is Dante from Devil May Cry 3. Corny lines and terrible delivery.
Gotta disagree Dante was pretty good in DMC3 with his lines needing to be corny since he's "Cool".

Best voice actor is a tough choice and you might have to say male or female. For female I would say the person that voices Bayonetta in the game of the same name. Her lines were delivered perfectly and the way she made the character sensual and caring was spot on. Best male voice would probably be Kris Kristofferson in for his VO of the captain of the NRC in FONV. Loved his somber delivery during his speech before he offs himself at the very end. Had a beautiful flow to it creating a heart felt promotion before *BAM* *THUD* and "WTH JUST HAPPENED?".
Worst voice actor of all time would probably be the main bad guy in Armored Core 2. His lines were good but it just sounded like he tried to force his voice being some British evil guy. As for the worst female voice that would probably go to the female owner of Datadyne on the Perfect Dark N64 console. Really found her voice over grating and not at all a good fit.