Not enough choices. How about at least adding "index options" and "all of the above"!? I trade equity, index and futures options.
You forgot to include Options on ETFs, so I voted pptions on stocks. QQQQ options for me, they have lower spread (usually 5 cents), and lots of liquidity.
You can trade options on FOREX via Interactive or MF Global. I'm sure there are a littany of others that I am not familiar with.