There are numerous Western businesses that have shops here in Nagasaki. I've already noted the KFC and some of the car dealerships. There is also a Toys R Us, a Claires, a Shell station, and numerous McDonald's. I'll note more as I come across them. There are supposedly Pizza Hut and Taco Bell joints in Japan as well, but unfortunately, I don't think they are in Nagasaki.
I've eaten at McDonald's twice. The first time I got a teriyaki burger. I was expecting a hamburger covered in teriyaki sauce, but it was actually a sausage patty (with mayonnaise and lettuce too). The second time I got a double cheeseburger, picture of the receipt is below. If you can't read the katakana, double cheeseburger in Japanese is romanized as daburu chizubaga. A double cheeseburger in Nagasaki costs about $3.00. I got a water with it (free), and the cup it came in was marginally larger than those little paper cups you get to put ketchup in. Another interesting thing about this receipt is that mizu (water) is printed in katakana, which is, according to my Japanese professors, a horrible sin.
Below are some random pictures I took within Toys R Us with my cell phone. They have a sizeable Halloween section and multiple aisles of Gundam toys and models.