I have this one:
Amazon.com - Eureka Enviro Hard-Surface Floor Steamer, 313A - Household Steam Mops
Works out alright. Does leave a bit of streakiness on the hardwood but I think that is pretty much unavoidable with steam mops. I use it as my "important company isn't coming over and I don't want my floors to look like shit" category then have actual hardwood cleaner/shiner and a non-steam mop to make them look really good if I care.