Topics I wouldn't be game for on a first date... Sex.
As for what I would discuss... man... On my last date I had to deal with a language barrier and that was no fun at all. There was also this preconception, on his part, that I would love to give him an English lesson on our date... I didn't. But, I did find that steering the conversation towards hobbies and interests helped a little. (He only had one hobby though...)
I find that playing a board/card game on a first date in a bar/pub usually works out. You can talk about the game, let out your playful/competitive side. And from there you can talk about other games... what you liked as a child, which leads to talking about your childhood and things just escalate from there. Drinks also takes the pressure off a bit. You don't have to sit there for a whole meal, worrying about what to talk about. And if you both hate it, you can bail after the first drink!