Medium rare across the board, including hamburger steak.
Rare for my steak, though medium rare is also good. If it’s a fatty cut, the fat should not be cold. Medium for my hamburgers.
Prime rib: As the chef prepares it. I don’t know if you consider that steak.
For most steaks: medium rare. Nothing to be gained by cooking more than this level, but you start to introduce risks into overall tenderness from outside to the inside and you add a layer of risk in terms of juiciness.
Rare. Unless it is crappy meat, then medium or medium rare. But, I’ve cut way back on the meat I eat and only buy quality beef.
Medium rare. My wife likes it real well done, to which I say feh.
Medium rare.
I’ve even converted my formerly medium-well-eating girlfriend.
Also known as Pittsburgh-style or Black-and Blue. That’s how I like mine.
Too many places over cook medium rare so it becomes medium or done. I order mine rare and usually get what I feel is medium rare.
Depends on the cut & on the cooking method
Typically go for rare - medium rare. Seared at high temp on the outside - still red in the middle
Pittsburgh.
Well done, of course. Many will consider me a heretic for liking my meat cooked all the way through, but I can’t bear the texture of undercooked meat.
I have had my steaks cooked by excellent chefs, who shed crocodile tears at having to “ruin” the meat. But if I’m paying, I want it cooked it until it is DONE!
I picked medium, but really somewhere between medium and medium rare is ideal for me. Usually I’ll go with medium rare in restaurants, as they tend to go a little more done these days than they used to.
I like it raw, but it must be warm in the middle. Ruth Chris Steak house can do this.
In most, it’s cold.
I know. I just hate even saying that word. Unless as part of the sentence “Packers crush Pittsburgh in Superbowl classic.”
I used to go medium rare, and in the last decade or so my tastes have shifted to medium. That is, it’s fully cooked but not yet charred.
At a good steak joint, though, just about anything between raw and charcoal can be made appealing.
(We have reservations at Gibson’s next weekend and I can’t wait! <homer> Mmmmm… Steak! </homer>)
Medium rare for me, please!
My mom was not a great cook, especially where mat was concerned, and most of the meat served at home was the consistency of shoe-leather. Consequently, I was very nearly a vegetarian growing up. I was in my mid-20s and living on my own when I discovered that steak could actually be tender and flavourful – a major revelation! Nowadays I loves me some dead cow. Mmmmmmm… beef! 
Medium rare, and if you’re going to err, err on the side of rare. Same with 1/2 pound and up hamburgers. (I don’t mind if my quarter pounders are well done.)
On the purple side of medium rare for most cuts like ribeye, NY strip, or sirloin. A bit more done (on the pink side of medium rare) with tri-tip, only because my wife does tri-tip in an awesome lime-garlic marinade, and the longer cooking time really allows the flavor to blend nicely.
Blue rare. Yum. Something that a good vet could revive. Nothing takes the pleasure out of a good steak like cooking it until its grey.
I like most of my meat well done. Especially when it has a bit of fat burnt to a crisp. My SO makes thin boneless steaks cooked to a slight crisp, covered with salt and lime and it’s the best.