Interesting enough, I just got some JL Audio speakers (front and back) for my car for Christmas. I have the back ones installed, and I'm going to have my friend install the front ones for me this weekend.
I think a car is a great place to listen to music. It takes me 40 minutes to an hour to drive to work everyday (and back home), and having some great quality speakers really makes a big difference in the enjoyment of the ride. It can even put you into a good mood going into work.
Also, I recently bought a pair of Audio Technica ATH-M50's for my desktop use. They're quite nice - good for gaming too.
Interior Crocodile Alligator, I Drive a Chevrolet Movie Theater