Out of the two, steak.
I've never cared for burgers, probably due to being fed a low quality one as a kid. Also I had a cheeseburger in Whimpy that made me sick, although that may have been more to do with the cheese than the burger. The problem with burgers for me is when they are on sale at public events, there's hot dogs too. Sausage is king for me (please insert cock joke). Whenever I've been dragged to a McD or Burger King (not often) I'll always go for the chicken option or if I stop at a service station and others go for something burgery, I'll head right for KFC. I'm not against fashioning my own burgers with some decent mince, onions, herbs etc, but if I were to start I can almost guarantee I'd end up shaping them into balls instead and making a tomato/chili sauce and doing them with pasta instead of actually proceeding with burgers.
I've never been much of a steak man either, I've always found the taste of beef/steak not to my palette, almost metallic to me. I guess I've always been more inclined towards the taste of other animals. When the household is going for steak, I will however take one rather than being awkward. Well done, inserted into a bun or sandwich with fried onions and English mustard.
Of course, transpires over here that you're probably eating horse when you think it's beef either way.