Petland! I completely forgot about that place. I only have Petsmart and Petco around here. I might have to go find a store if they have a good goldfish selection.
Goldfish are certainly happier with a buddy around. My two have been in their current 50 gal for about 5 years. They will often follow each other around the tank. Recently I had to put a divider in to let some of my plants regrow; when I removed it, they wouldn't venture into the "new" area unless the other was with them. I think they will be much more adventurous with another buddy in the tank. I did have a comet with them at one time, but I had to rehome him to a pond because he was a little too frisky for my fancies (and he grew like a weed).
I know goldfish are happy with a buddy, but I don't really know how many buddies are needed to make one happy. If the tank is in an area where they can see you often perhaps just one buddy with be enough. Goldfish aren't a schooling fish like many tetras but they do enjoy company.
Also I'm glad to find another goldfish enthusiast. Goldfish are often passed over in favor of most tropical fish, but I think they have a wonderful charm to them.