If raytraced games gain popularity the CPU wars won't be over yet, unless GPUs are quickly ramped with optimizations for that type of work. If I was going to make an engine analogy I'd probably compare CPU cores to # of cyilnders or physical engines, the transmission would be more analogous to hyperthreading or maybe a cache, the transmission just allows you to use your available work doing power more effectively for the job, the engine or cylinders do the work, beyond a certain point though more cylinders are just, well, more cylinders sucking down power at cruising speeds and making more power than the car can put to the ground (or instruction cycles that have nothing to execute in the case of a multicore cpu). I think you'll see software morphing to use the power and at least 8 cores can be used effectively in a desktop PC in the future, a big hurdle will be using stuff like the crossbar bus etc and making the hardware more able to deal with and take advantage of splitting threads to individual cores to continue to see large improvements in performance.
Most 6 speeds out there are for fuel economy, gears 1-5 are performance gears and 6 is way overdriven to get good highway MPG, as an aside.