I prefer a mix of both. When I went to Europe, I could have focused on getting more creds, but instead I focused on seeing the cities and doing that sort of thing. I still got some creds when it was close and convenient though.
As people have said, the Italian Live was a good mix of culture and creds. We seen Verona, a bit of Bologna, and Rome, as well as getting a lot of creds too.
In America, I don't care AS much, depending on where I go. I will take the opportunity if there's a city I'm interested in seeing, but so much of America is so alike that sometimes I just don't care.