I've always called them Square. I played FFII for the SNES first, and it says "SQUARE" on the cartridge, and in the game at the title screen. I learned that the company that made Final Fantasy II was called Square, so that's what I called them when they made FFIII, FFVII and so forth.

I know they were technically called 'Squaresoft', but we just never called them that. Meh.

But I really don't like to call them "Square-Enix". I know it was a mutually beneficial merger and it probably won't make their games any worse than Square was going to make them anyway, but even so. The name "Square-Enix" just seems lame.

"Squeenix" is slightly cooler. Slightly.