After listening to audiobooks in my car for over a year now, I can honestly say they have opened up a whole new world for me. First, it's a great way to make my 30-45 minute commute much more enjoyable. Second, and perhaps more importantly, I find I am discovering books I probably would not have actually read.
Although I have never been a voracious reader (unlike my wife and daughter) SciFi and gritty Fantasy have been my staples, but by listening rather than reading I have devoured several books I had tried before but never finished reading: Frank Herbert's Dune and Asimov's Foundation Trilogy are good examples of those.
Now, this enjoyment can of course depend upon the skill of the narrator, but with very few exceptions that has not been an issue. The audiobook producers seem to be very aware of this and most of the voice actors or narrators are at least good, and some are truly outstanding.
I have also found, perhaps oddly, that it does not distract me from my driving. To the contrary, after navigating some tricky stretch at rush hour, I will find myself rewinding to catch up on a section of the book I that had "tuned out" in the interim.
The nice thing about modern technology is that you are not mucking about with cassette tapes and the like. Those of us who made it through the 1970's and 80's know how cassette tapes and hot car interiors don't mix.
For me, the audiobook phenomenon has been a revelation - some days I find myself looking forward to the morning drive to work to catch up on whatever the characters were doing when I pulled up in front of my home the previous evening. That's pretty powerful.