Ianto/Jack/Martha
The same thing is true with my family too, actually. We all got along a lot better once my brother and sister and I had moved out. Well, except for my parents.
[...] Jessica and Trish are the ones from the universe with the Doctor's look-alike, aren't they? I'd hate for them to have to deal with him if he came over to find me. I don't know very much about the others. Well, except the Weasleys and Potters, obviously.