What are the differences/distinctive between the Anglican and Episcopal churches? I've never been very sure what the difference is between the Anglican and Episcopal churches. Is it safe to assume that in core doctrines their doctrinal stance would be pretty similar, i.e. Christology, soteriology? The impression I get is that the Anglicans are more traditional (e.g. view of authority of the Bible) and Episcopal more "progressive" (forgive me for using a loaded term).

What would be the differences in terms of the following: doctrine, practice, polity, confessions/creeds?

Any other differences of note?
Anglican Churches and Episcopal churches are almost all members of the Anglican Communion, a group of churches all associated with the Church of England. As such they all subscribe to a similar theology - e.g. the historic creeds, ordained minsters overseen by bishops, infant baptism, liturgy, sacraments. You can read more details at the Anglican Communion Doctrine page.

Whether a church within the Anglican Communion is called 'Anglican' or 'Episcopalian' is more a matter of history than doctrine. Churches tend to use the name 'Anglican' in countries with strong historic ties to England (Australia, Canada, South Africa), and Episcopal in countries without those ties (Brazil, USA, Philippines) but there are exceptions to both of those. Some members of the Anglican communion use neither. Doctrines of individual churches within the Communion also vary, but there is no correlation between the name and the doctrine.

Anglican and Episcopalian churches are also well-know for the breadth of their beliefs. Beliefs of Anglican congregations, or individual members, can range from 'virtually Catholic' to 'strongly evangelical'. 

So there are no distinctives between Anglican and Episcopalian churches in general, although there will be differences between individual Anglican or Episcopalian churches. There are beliefs and practices that distinguish the Anglican/Episcopalian community from other churches, but even then there is widespread variation in practice.