I love this thread! I grew up with the NYC subways, when you had to keep straight if you were riding the BMT, the IRT or the IND lines. It is still one of the best values-- being able to ride the system plus one transfer for $2.75, especially when compared to the time and expense of any other method of transportation in the city. So, I go out of my way to ride the subway, if at all possible, to/from airports and then to get around.

I will tell you, absolutely, the Q70 non-stop bus to Roosevelt Avenue, where you can connect to the E, F or 7 train, is the only (almost) sane way of getting out of LaGuardia-- as the express busses (Q70 and M60) are the only vehicles allowed to come right up to the curb-- otherwise you are on a shuttle bus to a pick up spot.

One of the factors, to me, that makes a great subway system is the efficiency especially when compared to the alternative of riding in a cab or bus above ground. Here, I think that Shanghai and Beijing are amazing, even with their faults, as both cities are nightmares to be stuck in a car, and the subways are efficient, widespread and cheap. I put London right behind them, as long as you have a tube map.

DC is great for to/from DCA, but pretty lousy for everything else-- especially the aged red line, which has truncated service or maintenance issues every day.

The one greatest disappointment is Chicago-- while the traffic to or from ORD is horrible, the blue line is so slow, and the closest you can get to the Michigan Avenue hotels is Clark/Lake, which still means a hike with luggage, not to mention trying to get out of the station onto the street there with luggage. The service around the loop may be good, but if you are further uptown, there is almost nothing.

I agree about PDX being efficient--Denver not so much.