Reusable rockets? double the fuel ?

Just hopped across this SpaceX's Grasshopper video which made another feat this month.

Is it good (or i would prefer the word feasible to introduce re-usable / balanced re-entry rocket considering the cost of building one rather than burning around double the fuel required to take one up ?

(Not to forget, if it plans to come back down right from hundreds of Kms, it would carry large amount of fuel. That would require some more extra quantity to actually lift it to space in the first case)

Sure the fuel required to get back down is lesser as the work is done just to slow down its free fall but that too by dynamically balancing it all the way ?
But that stuff they do there seems really cool .