Two other ramen favorites of mine.
山頭火（さんとうか Santouka）has quite a few restaurants around the Tokyo area, and you can even buy their ramen in the supermarkets. My favorite is the salt ramen (塩ラーメン）. It's a very tasty, flavorful soup. The pork is average if I remember correctly, but they have a special とんとろ fatty pork version which is particularly delicious. The pork is tender and tasty. A bit salty though, so a little pork goes a long way. The noodles are normal but not bad. I love the salt ramen so I've never tried their miso or soy sauce versions. They have a nice soy sauce egg that you can add as a side topping.
一風堂 (いっぷうどう Ippudo）also has quite a few restaurants in the Tokyo area, but most of them aren't very convenient to get to. Ippudo is a Hakata style ramen place, so their specialty is my favorite soup, tonkotsu. Their tonkotsu is flavorful and a bit on the heavy side. The pork was not bad, and the noodles are quite good. They also have lots of toppings like garlic and I think kimchee? so you can have a lot of fun with your bowl of ramen. The last time I went I had a little too much fun crushing fresh garlic into my ramen, and my body got kind of upset with me, but it was delicious. Ippudo lets you specify the hardness of your noodles, and they recommend the moderately cooked noodles. Since I am not a true ramen fanatic I always get the softest version available (recommended for children) but I like it that way. They offer two types of tonkotsu soup, 赤丸新味 (あかまるしんあじ akamaru shin aji）red bowl new flavor and 白丸元味（しろまるもとあじ shiromaru moto aji）white bowl original flavor. The red version is a thicker tonkotsu soup, and the original flavor is a bit lighter.
Next time I'll write about a new tonkotsu favorite, Tou soba.