There are many excellent pets for people who live in cities. Personally, I want a dog. However, my current lease does not permit them, so I will have to move first.
I think that Dogs make great pets because people of the close bond that they share with their owners. However, many dog owners say that the responsibility of owning a dog is larger than they expected.
Cats are much easier to take care of, although I (like many other people) am allergic to them.
Fish are much easier to take care of, and they are fun to look at. However, they don't really bond with their owners.