When I was an Anglican, people often commented about the port used for Holy Communion. They typically liked it. There is an interesting history behind this custom.
As you may know, England does not produce wine. Everybody loves a bottle of "French wine", but who has even heard of a bottle of "English wine". So wine was mostly imported into England.
However, after the Restoration of the crown and episcopacy at the end of the 1600s, the War of Spanish Succession pitted England against Spain and France. At this time, France did not export wine to England. In 1703, the English and the Portuguese signed the Methuen Treaty and became political allies against Spain and France. This alliance also confirmed low import/export taxes between England and Portugal.
As a result, the unique fortified wine of Portugal was almost exclusive imported into England. The Portuguese wine was fortified as a preservative for storage and exportation. At the time, "wine" in England referred exclusively to what we know as "port wine" or "porto". If an Englishman served wine at his table in 1705 it was certainly "port wine" from Portugal.
Thus, it became the custom for the Church of England to employ port at Holy Communion. Since liturgy is naturally conservative and old habits die hard, port has remained as the communion wine of choice and most Anglican and Episcopal parishes.