In general, Port has sweet, fruity flavors of ripe berries, figs and raisins with hints of toasted nuts.
The style of Port you're drinking - white, tawny, ruby, LBV, Colheita - can greatly affect how successful a cheese and Port pairing is. The five cheeses below may not pair perfectly with all different styles of Port, but they do give you a good place to start. As with most pairings, experimentation is the key to finding a match made in heaven.
Stilton is the classic pairing with Port, not only because the salty, nutty nuances in the cheese pair beautifully with the sweet wine, but also because of Great Britain's long history of being involved with the wine trade in Portugal. If Stilton isn't your favorite blue cheese, then go ahead and try your blue cheese of choice with Port; in most cases, you'll find that whichever blue cheese you choose, it will make a fine pairing with Port.
Other blue cheeses to try: Gorgonzola, Great Hill Blue, Cashel Blue
Another English cheese makes the cut as a partner to Port, this time an earthy, nutty and fruity aged Cheddar like Montgomery's. The Port brings out the nutty and creamy characteristics in a farmhouse cheddar and the two paired together are almost satisfying enough to be a meal. Give other aged cheddars a try too, either domestic or imported.
Other Cheddars to try: Beecher's Flagship Cheddar, Bravo Cheddar, Cabot Cheddar.
Azeitao is a Portuguese cheese that makes a good regional pairing with Port, but also makes the list because of it's creamy texture and nutty nuances. Thistle rennet gives Azeitao a grassy and tangy character that can be smoothed out by the sweetness in Port, although occasionally it is exaggerated by dessert wine. The smooth, sometimes runny texture of Azeitao is a luxurious combination with the rich texture of Port wine.
Other Portugese cheeses to try: Sao Jorge