APM, it looks like your tank is about 37 US gal, or 31 UK gallons. This would be a good home for two or three goldfish, depending upon the types you get.
As for the ornaments, that's just a matter of personal preference. Nothing too pointy that they might damage themselves on, and nothing so large that it makes it difficult for them to swim.
Do you have any fish yet? Have you read up on cycling?