My favorite new street is over by the Hannam UN Village. It's the street where my friend Johnny has the Naked Grill. If you come out Hangangjin station, you take a bus to Dankuk University and cross the road and go up the hill. I know not convenient to get there, but it's worth the walk. If you look at this post, it has better directions. My friend Ben went to the Naked Grill today for a cheesesteak and he said it was pretty awesome.
So what else is up there? There's the Banana Grill for good hamburgers. They're not the best in Seoul, but they are decent. I had the mushroom burger and it had good (but thin) meat in a plush (but too big) bun. I also went up to the Naked Grill for a pancho burger. The Naked Grill makes good tacos, but their burgers need a bit of work. I found the meat a bit gristly, but the pico de gallo was good and the price wasn't too expensive. I recommend their tacos (you'll often find the taco truck parked at the Hard Rock in Itaewon.)
There is a new taco joint. I didn't eat there, but it looked pretty popular.
Also, across the street is Puffin Cafe. I wouldn't say that this is a place that has "good eats." Johnny told me that this was the brunch place that started the craze in the city, but quality has really gone done. What can you expect? According to Johnny, thin ham steaks cut from the kimbap ham (processed crap) and runny eggs.
You will find Chakraa there and they have good curry. (I mean they have to because the Indian Consulate is up the hill and they have high expectations.)
I chatted with the woman from Lynn's Cupcakes there and had a "Red Velvet Cupcake." This was pretty darn good. Bart Simpson would have stolen 20 of them.
It's a good street and pretty quiet. I recommend you take a stroll.
On my way home, I stopped at the new Pizzarium for a beer. I ate there last week and the pizza was great. The last time I was there, I felt the crust was too moist, but now it's a crisper and cushier. I recommend the tuna pizza and the mushroom.