"Best" wheel for the money...there is none in retro. It really depends on the application you are using this wheel for...also, you need to match your tire with the wheel, size, width, etc. Not only this, but your suspension setup will have an effect on what type of tire/wheel combo you would want to use (not just due to size, but getting the "best" suspension setup possible using all factors avaliable to you).
I would say the best bang for the buck would be to start at the flywheel...since rotational mass (like mentioned before) has a sort of multiplier effect on weight and real enging HP.
4wheels x 5lbs a wheel x 3 = 90lbs
4 x 5 = 20
20 x 3 = 60
what ever the freak that means
From the formulas listed earlier:
1) Wheels/tires = "Unsprung Weight"
2) Unsprung weight has a 1:3 (1 to 3) ratio on sprung weight.
3) 5lb lighter wheels (unsprung weight) is equivalent to losing 60lbs of sprung weight.
Lets look at that another way:
Wheels = unsprung weight
Rear Seat = sprung weight
Say your entire rear seat assembly and attaching hardware weighs 60lbs.
By losing 5lbs of weight at each wheel (20lbs total), you would gain the same performance as pulling the rear seat (60lbs) out would.