I've also done goldfish in a community tank, but here are my problems with that sort of setup:
1) Goldfish get BIG. Even fancies are large enough to eat many of the common community type fish. Also, goldfish are bullies. They'll most likely end up playing with smaller fish, stressing them out.
2) Goldfish excrete a LOT of ammonia, and most community fish are more sensitive to ammonia than goldies.
3) Goldfish are piggies: they'll eat all the food that you mean to give to the other fish, so you'll have to be very vigilant to make sure everyone is getting fed.
4) The amount of filtration/current needed in a goldfish tank can be difficult for many other fish to deal with.
5) Goldfish are destructive. Any and all decor will be rearranged up to several times a day, and any and all live plants will be food. I've had some success with anubias in goldfish tanks, but anything else was gone the next morning.