After about 14 ounces of anything, I get bored. and that goes for steak, too. So, when I find myself eating a big dry-aged piece of beef for dinner, I don't force myself to finish it, because I know great things will be happening for lunch the next day.
One of my favorite uses for leftover steaks is the classic thai beef salad, often called yum nuea (the spelling varies). It consists of sliced steak over greens, with an acidic, sweet, salty dressing made from fish sauce and lime juice, thinly sliced shallots or red onion, definitely some ground toasted rice and some herbs like mint and cilantro. But that's not important right now. It's more important in the summer, but not right now.
What's important right now is a steak sandwich. And I don't mean steak 'ums, or even thinly sliced ribeye a la philly cheesesteaks (which certainly have their place and can be quite delicious). I'm talking about a hardy sandwich with sliced left-over dry-aged beef, on some crusty italian or french bread (Jerry's Gourmet or Balthazar, both in Englewood, are fantastic sources), with some fresh arugula, caramelized red onions for sweetness, and a yogurt/horseradish sauce (yogurt, fresh or jarred horseradish, a little mayo, a little salt). And that's basically it.
I heat up the steak in a covered pan so it gets a little warm. You obviously don't want it to cook through. I don't care what kind of steak it is. Although i'm usually buying strip or ribeye. Slice it thinly (against the grain, please), and assemble a sandwich. Open or closed, it don't matter.
Don't underestimate the importance of the freshest arugula. There's nothing quite like super-fresh arugula. Those who have picked a leaf right out of the ground will tell you how peppery and spicy it is. almost to the point where it feels like it's burning. Each day it spends out of the ground is another day it gets closer to turning into, well, spinach.
So, go buy some steak for dinner. And buy some extra too.