There's lots of potential with this setup, the primary limiting factors are going to be how much time and money you want to expend tricking-out your new chair.
Something not yet mentioned would be sound. Whether it's just hacking an MP3 player board to controls on an armrest, or doing a full custom sound system including speakers, radio, and microphone; you've got some options there as well.
With wireless modules like Xbees, you could also turn lights and some appliances on and off on command, or automatically as you moved around your home.
I have some other ideas but they start getting into the "way too expensive and/or eccentric" territory.