Is it better to get your bachelors and masters/doctorate from different colleges?

Whether or not it's "better" depends on the degree and what you are going to do with it, as well as the reputation of the colleges involved. Attending different colleges may be seen as a plus because it adds diversity to your educational background. In some cases though it may be considered a negative.

For example, if you were an education major that got your bachelors degree from a university that was very well known for it's education department then you would probably also want to go to grad school there because of it's excellent reputation for that major.. If you wanted to be an education major and teach, then it might seem strange that you left a great teaching college for one with a lesser reputation in that field.

As for choosing a completely different major for your masters, that's possible, but not always a wise choice. Many masters level courses can have prerequisite requirements that you may not have if you had an unrelated major for your bachelors.

You best option would be to sit down and talk to an academic adviser about your goals to plan your course of study.