Determining the "best" fighting sword of all time is subjective and can vary depending on various factors such as historical context, cultural preferences, and personal opinions. Many swords throughout history have been revered for their design, effectiveness in combat, and cultural significance. Here are a few notable swords that are often considered among the best:

1. Katana: The katana is a traditional Japanese sword known for its distinctive curved blade and exceptional sharpness. It was historically associated with the samurai and is renowned for its cutting ability, balance, and craftsmanship.
2. European Longsword: The European longsword, popular during the Middle Ages, was a versatile weapon that allowed for a range of techniques. Its design evolved over time, with different variations across Europe. Longswords were known for their length, cutting and thrusting capabilities, and their use in armored combat.
3. Roman Gladius: The gladius was the primary sword used by Roman infantry during the height of the Roman Empire. It was a short, double-edged sword optimized for close-quarters combat. The gladius' design facilitated quick, powerful thrusting strikes and was highly effective in the Roman military formations.
4. Chinese Jian: The jian is a traditional Chinese double-edged straight sword with a history dating back over 2,500 years. It is renowned for its balance, precision, and versatility. The jian was considered a symbol of status and martial prowess in Chinese culture.
5. Scottish Claymore: The claymore was a large two-handed sword associated with Scottish Highland warriors. It featured a long blade and a distinctive crossguard. The claymore was known for its reach, power, and its ability to deliver devastating cutting blows.

These are just a few examples, and there are many more remarkable swords from different regions and eras that have made an impact in their respective contexts. Ultimately, the perception of the "best" sword is subjective and influenced by historical, cultural, and personal preferences. Each sword has its unique characteristics and purpose that made it effective in its historical context.