HypermilingNoob,
this really depends on what your goal and budget are
a pound of wheel is worth about 2 pounds of non-rolling car weight
so even if you save 5lbs a wheel - that is only 40 pounds total
you will never see the savings at the pump - it is too small
and it will never pay back the cost of new wheels
for racers with budgets - wheels are an easy way to save weight
at the drag strip you should notice a 40 pound reduction in your times
but if you just happen to be dropping $1000 in wheels anyway
or have a low/no cost source (salvage etc.)
make sure they are light
Christ,
nice link