I set up a make-shift mount in my car for my iPad 1 (a series of velcro straps that create a loop between two of my AC vents, so it hangs in front of my stereo/AC controls). Not hard to move it out of the way for quick access to those controls. I do plan to replace my stereo unit for one that has front-panel AUX input, as my current setup of sending audio via Bluetooth to my Ibiza FIPO that connects to an FM Transmitter lowers audio quality a bit too much.
I just load it up with audio and video podcasts. Revision3, TWiT, The Onion, No Agenda, IGN, 1UP, Beer School, KnowTech, etc. Works great with my MyFi. I am holding off on a 3G iPad or switching to WiFi tethering with AT&T until they get 3G in my area. Closest 3G area is about 15 minutes away from me, getting closer.
In a car the iPad actually works better as a CD-changer replacement, as it can hold far more music. I usually just load 2 or 3 custom playlists, 5 custom genius playlists, and 6 or 7 of the auto-generated genre based genius playlists.