All I can say, as the one person who cares about the budget, is:
Not bailing out whichever administration inevitably causes our surplus to vanish because "it's not like we can't afford" any of the 120 other things we'll be allocating boatloads of cash to in the meantime! 
Well, the reasons why we have to move the capital have been stated before. Will this require a cost, yes. Obviously. And sure, we do have to be careful with budget
But the goal of a government should be to invest so that people / the government can even get wealthier and have bigger returns. No investment and no spending is stagnation.
We are running a surplus of $1044.28 Billion. What happens with that money? It should be spent. It's not healthy for an economy to have that much reserve. No government globally does that.
If we want to dwindle the surplus I'd rather we return it to the people in the form of tax cuts and rebates rather than follies like relocating the entire government.
