A raincoat is highly recommended!
Photo Equipment: A good camera with lots of film, a tripod and telephoto lens and a waterproof bag to carry all your gear in.
Miscellaneous: Cordova receives 92.08 inches of precipitation and 118.89 inches of snow each year according to the FAA's 30 year study (link below)
Luggage and bags:
Be sure to pack overnight clothes in your carry on because there is a small chance that you miss the flight from Anchorage to Cordova, but your luggage makes it, or vice versa. The Cordova airport is wonderful about connecting you with your luggage if you get seperated.
Clothing/Shoes/Weather Gear: Bring your rain gear! There is usually a light rain several times a week, and the summertime high temps are usually in the 60's. Occasionally it will hit 80 degrees, and the town shuts down and goes on a picnic to the glacier or a favorite fishing hole.
Toiletries and Medical Supplies: There is a hospital in Cordova in case of any emergencies (and since I broke my leg in Cordova, and had the opportunity to be treated by the staff at the hospital, I can assure you that you are in great hands if you ever need their assistance.), and there is a general store (Alaska Commercial) for minor items such as band-aids, etc.
Camping/Beach/Outdoor Gear: Don't forget your fishing pole! The silver salmon fishing hits it's peak around the end of August / early September, and halibut fishing is best in May. Cordova is the home of the famous 'Copper River Salmon' which has been voted to be the best tasting salmon in the world by many people.