for me it would be either, from Sega master system to PSX or from Walking to MotorBike.
The bike would have to be the best but I was amazed by the improvement of the PSX over the master system at the time, I had gone from an extremeley dated console to te best money could buy the year the PSX came out.
Think my next best upgrade will be going from Bike to Car but that has yet to come
