If its just a bit of fun movie, I used a Nikon camera taped to the grill of my brother citroen C1 - gave a brilliant low angle and engine noise.
not as professional as what others suggest - but if its just a movie for a bit of fun - it gave quite good results. I will try and get a sample uploaded! ... somehow!
a selection of cable ties and black gaffa tape was used currently trying to work out you tube to get it uploaded! (btw it was an old camera - thats why I wasnt worried about a stone hitting it or something)
I have to say I've never been impressed with the Gopro footage I've seen.
I've used some professional mounts (that were not cheap in the slightest) that my best friend uses. But he makes films for a living. Tbh his camera and mounts cost more than my car so it was bound to look epic :lol: