Street Dominator with some light plenum work (this can be done even with a small rat tail file). Low profile (lower than the RPM), nice low end torque, very good power, looks good and can be found cheap (read: used).

The RPM would be a not too close second, but way ahead ov anything else. The Edelbrock (non-RPM) dual planes and the Mopar dual planes are too close to the stocker to bother, unless you just want the weight savings.