Do you have over pronated feet? NB 903 is a stability performance shoes for over pronated feet. I just bought a pair myself (see my thread). I have yet tried it for a LSD (over 15 miles) so don't really know how good it is. But it is excellent for short 10Ks and intervals. The heel isn't as thick as the Asics 2130 or 2120 (last years model) though. Try the Asics 2130, one of the most popular running shoes in North America besides the Asics Kayano 14.
Oh , make sure you get yourself a good pair of arch support insoles for your new shoes.