I use an ATC 3K for karting (a bit overpriced at £100, I bought mine cheap off a friend) and it happily does 30fps at 480p. For in car use, I strap my old LG Viewty (same res and framerate) to the rear view mirror and the quality surpasses any reasonably priced action camera out there!
My friend recently bought a Countour HD for his motorbike, which looks fantastic but is pricey at £250ish. I've attached some piccies for comparison:
^ ATC 3K (£100 RRP)
^ LG Viewty (£80ish RRP now?)
^ Contour HD (pic stolen from Youtube so horribly compressed, RRP £240)