The game that would make me really motion sick was Turok on the N64. For some reason it would only make me sick if I watched someone else playing it. If I played it I wouldn't get sick at all, as weird as that is.
For those that have recently started getting motion sickness from games, I'm wondering if it has anything to do with the refresh rate on TVs. I can't stand 120Hz or more, because it gives the picture a 'soap opera' type of movement, or it looks like the game/movie is being fast forwarded which causes some motion sickness with me.