Sony 7506 is right on, they are the flattest standard head phones to use, nothing is more reliable, and all else are good only for isolation from loud drums or instruments in general.
The ref monitors are too high, unless your planning on standing up to mix.
Why dont you just settile your CPUs side by side in the center, monitors where you can hear them head level, and all yourkeyboards on stands, this way under them you can have your DJ rig and use this all live as well in the ...