My favourite ramen place in the city -- well, granted, I only know of two (other being Kenzo). I still have yet to try the okonomiyaki at Kenzo so my allegiance still may shift in terms of preferred restaurant, but my vote definitely goes to Ajisen for a bowl of ramen. Mmm!
Update: I found ramen on this continent (in New York) that was a gazillion times better and I can never go back to the grease soup and non-legit noodles that is Ajisen.