I like seeing PDX
on the list, and for a city of its size, it is definately good. In the US, however, I'd have to say SFO
- good coverage, generaly good frequencey (except f market.. I think thats the one), good schedule (even late), and most importantly- I feel safe. While its not all shiney and new, I've never felt as freaked as i did in the NYC subway.