What if you're the ruler of a nation with plenty of money and looking to build a world class airforce after WWII. There are plenty of surplus warplanes of all types going into the scrap heap that could be had for a song. In fact Sweden managed to assemble the 4th largest airforce by 1950.
The key is to chose planes that will give not only high performance but remain useful for as long as possible. Besides fighters, attack aircraft and bombers, you'll also need trainers, transports of all sizes, sea planes, and maritime patrol aircraft. Assume you have good relations with everyone. So what would be your choices?