Of the three handgun choices, I guess the Glock would be my first choice. Mainly because of the weight, 26oz. Compare that to 36oz and 38oz, respectively. Plus there are only 33 parts to fool with and a case for the gun. Also, tear downs are made easy thanks to the included tool. Second, would definitely be the Springfield Armory GI 45. How cool would it be to have a replica of what our troops carried into combat during WWI and WWII. There is nothing sweeter than that. Finally, the Llama 45. Almost completely based on the fact that it is half of the others in price. Who am I kidding, I would not even consider it if it wasn't for the price.
Now to find $600.