What cities have you used public transportation? (car, money)

[BVitamin]

Irvine
San Francisco
New York City
Jersey City
Hoboken
Boston
Rome, Italy
Milan, Italy
Pretty much all of Jamaica

[Katiana]

Geographically (sort of)
City transit services:
Pittsburgh
Beaver Falls, PA
Boston
Wilmington, DE
DC
Champaign, IL
Chicago
Denver
San Francisco

Greyhound:
Butternut, WI to Milwaukee, WI (RT)
Pittsburgh, to Bloomsburg, PA (RT)
Pittsburgh to Frederick, MD (RT)
Pittsburgh to Confluence, PA (RT)
Denver to Omaha (OW)
Some sort of intercity bus from Chicago to Champaign, IL [was not Greyhound] (OW)
Merrilville, IN to O'Hare Int. Airport (OW)

Ferries:
Seattle, WA
(Also in Vancouver, BC)

Train (pre and post Amtrak)
Beaver Falls to Milwaukee (RT)
Champaign to Chicago (RT)

[californio sur]

I take the Gold Line [light rail] from Pasadena into downtown Los Angeles fairly often & then switch over to the Red Line subway to Hollywood. Aside from buses, those are the only trains I have taken in LA. In San Francisco I have been on numerous street cars including the one that goes thru the Embarcadero as well as the cable cars from Union Sq to Fisherman's Wharf. Also the BART train from SFO to downtown San Francisco.

I took the # 2 & 5 trains from the Bronx into Manhattan, plus the L\ Canarsie to Brooklyn and the A train thru Queens out to Rockaway Beach.

[star314]

Denver, Colorado (as far as Aurora and Golden)

Should be looking to try Dallas's soon, hopefully ...

[BPerone201]

NYC/NJ, Philadelphia/Trenton, Baltimore, Boston, and New Haven.

[phxgreenfire]

US
San Francisco/Oakland
Los Angeles
Portland/Vancouver, WA
Las Vegas
Phoenix
Albuquerque
New Orleans
Washington, DC
New York
Atlanta

International
London
Paris
Berlin
Munich
Tübingen/Nagold
Frankfurt
Moscow
Seoul/Incheon
Uijeongbu/Dongducheon
Hong Kong
Hiroshima
Tokyo
Osaka
Bangkok
Hong Kong
Sydney
Rio de Janeiro
Buenos Aires
Colonia del Sacramento
Toronto

...anywhere else was via car or coach.

[Crown Vic...]

DC, NYC, Baltimore, SF, ATL, Philly, Boston

[DC's Finest]

DC, NYC, Chicago, LA, ATL, Minneapolis, Philly, Boston, Bmore, Dallas

[PDX_LAX]

I try to use the subway whenever I'm in a city that has one, I think its fun and coming from a subway-less city there's still a novelty in using it.

I've used it in Los Angeles, San Francisco, Boston, New York, and Washington DC. But none of them enough times to really know which were the best/worst.

I also use public transportation a lot in Portland and Seattle whenever I'm there.

[testa50]

This is only counting intracity mass transport (not long distance trains or buses, or things like airport shuttles). In general I like to walk, so I usually don't use mass transit unless it's totally necessary or I'm exhausted.

USA:

Atlanta
New York
New Orleans
Boston

International:

Toronto (subway)
Mexico City (subway)
Guanajuato, Mexico (bus)
Cape Town (commuter rail & minibus)
Blantyre, Malawi (minibus)
Harare, Zimbabwe (minibus)
Addis Ababa, Ethiopia (minibus)
Harar, Ethiopia (shared mototaxi)
Cairo (subway, minibus)
Istanbul (subway, light rail, boat)
Plovdiv, Bulgaria (commuter rail)
Pristina, Kosovo (bus)
Vlore, Albania (bus)
Paris (subway, commuter rail)
Barcelona (subway)
London (subway, commuter rail)
Glasgow (subway)
Stockholm (subway)
Hong Kong (subway, bus)
Christchurch, NZ (bus)

Probably more I'm forgetting.