Nobody's mentioned House of the Dead 2 yet? So many bad lines, you wonder if it was intentional.
Demon: "Suffer like G did?"
Agent: "I hope that's not G's blood"
Victim, to monsters: "Don't come! Don't come!"
"WE'RE meeting... GEE... over THERE." First lines in the game, delivered with a very Shatner-esque inflection.
Geez, how I saved up for a Dreamcast, along with two light guns, so that me and my buddies could play HOTD2 when it came out on 9/9/99. Having only played the first game in the arcade up to that point, I thought that the second game would be better in every regard. Um... let's just say that it didn't make the best first impression :-\
Agreed with some of the other posts, I think the original Resident Evil is the obvious choice for worst voice acting in a video game. I'd put House of the Dead 2 in second place, and for third, I'd go with the original Sonic Adventure.
It's amazing how impressive voice synthesis was in older games, especially when you weren't expecting it. Thirty years ago, my reaction would always be something along the lines of, "Holy smokes, the game's TALKING TO ME!" Nowadays, not only do we expect our games to talk to us, but when they do, we tend to be critical of it. I know it's not the same, comparing something like Berzerk to Skyrim, but it is a sign of just how far things have come.
On a side note, if I ever have the option to turn voice acting off and just read text instead, I do it nearly every time. Hard to be critical of the "voices in my head!"