I love goldfish too, I'd die for the chance to get a pond implaced in my backyard...it'd be fantastic!
I dunno what I'd do for winter though, because were we live there are many days of an average of 10 below
And after paying for my pond, I dunno if I could afford a indoor tank with a filter big enough!
I could very easliy set up a little cheap pool thing in my basement, but a filter would cost more than i could ever afford, esoecially since I'd keep koi!