Use DOT 4 or DOT 5.1 fluid. The best readily available brake fluid is Castrol LMA - found at any auto parts store. Other very good fluids are ATE Super Blue or Motul RBF600. Seems the Motul is the best performing, with the highest boiling points. This is what you want for feel and performance - the higher the boiling point the better.
Do not use dot 5. It's silicone fluid and is designed for garage queens - it compresses and vaporizes under hard braking. The advantages are once flushed in you will never have to change it again, it doesn't eat paint, and it will not corrode hydraulic parts. (think show bikes/cars). DOT 5.1 is the same as DOT 5 silicone.