Several months ago, Beth Cyr shared a wire straightening technique: Roll the wire between two steel blocks (see it here).
I use straightened round wire in a lot of my work and I use a flexible shaft technique to make LONG pieces of super straight wire:
ALWAYS WEAR EYE PROTECTION!!
-Place one end of the round wire into a vise.
-Insert the other end into a flexible shaft chuck jaw.
-While holding the flexible shaft handle, pull the wire taut.
-very SLOWLY press on the rheostat pedal...continue to pull the flexible shaft handle taut.
-Stop when the wire is straight and work hardened.
If you use square wire or put multiple pieces of wire together, you will make fancy twisted wire. Maggie Joynt showed us how to make twisted wire with square wire using the flexible shaft here.
Have fun and be safe!