Best Dan Dan Mien [London]
Been a while, but the best I had was the version at No. 10 near Earl's Court. The minced pork is properly crispy, and the oily sheen on the noodles has the right bit of numbing spiciness. Wish it wasn't as peanutty, but otherwise good.
Love to hear of other versions -- how does Er Mei (aka Empress of Sichuan) or Bar Shu's version hold up (haven't been to Barshu in a long while and it has undergone various chef changes).