Good GOSH I envy you. You definitely just purchased my #1 car, color and all. Highly respectable choice.
With regards to ideas, I think the key here will be the subtlty of the install. TVandNav2GO looks fine, however, I would use them only for fabricating a stock looking dash. If you want a real car computer, you need to personalize and do it yourself, catering to your needs. Dont do the huge LCD screen just to have that, you would take away from the car.
Most definitely utilize the IBUS to integrate the computer into the car itself.
Please, above all though, dont let us down on this. There are a few other amazing M3 installs, and if you want to be the hot ****, its gonna take some serious work.