If you're worried about your wife enjoying the movie (as well as you), then it really depends on your wife's tastes. I don't know her at all, but if I had to guess, I'd say that the "usual woman" (such a silly statement

) may prefer Fast Five over Thor. My thought is that Thor is probably a little nerdier especially with all the weird Norse terms (Mjolnir, Bilfrost, Asgard, etc).
I saw them both yesterday and liked them both. In my opinion, Thor is the better movie though. If you replaced Paul Walker, Fast Five would have a much better shot... that guy can't act.