I think there were a range of elements which have drawn me to this series, so I tried to break them down;
Firstly, a big draw for me watching this series was Paul McGann. I have been following him since I first saw "Withnail and I" a movie co-starring Richard E. Grant set in the last days of the 1960's for two out of work actors. He is a stunning actor and it is refreshing to see him in a new context (he played the Doctor in the 1996 Dr Who Telemovie and Lt. Bush in the fabulous Hornblower series).
Secondly, and I know a lot of people will agree with me that the idea of travelling while unattached is gloriously romantic and being a hopeless romantic myself I was immediately captured by the idea of travelling around the world and problems that occur...not that there should be any.
Other reasons for my attraction to this series was the other cast members, the sharing of the story across two continents and the incredibly moving scene which changes everyone's lives in the first episode. I guess I was pretty daft not to pick up what was going to happen, but because I didn't it effected me more. Wow! I am already keen to see what happens next.