If the government is intent on spending money, I think that investments in energy efficiency are the BEST choices. Reliance on imported petroleum works just like a tax on everything that we make, consume, or do. Let's say that a company produces 100K in products, and of this cost 10% of it is derived from energy and petroleum products consumed during production. If we import 70% of our petroleum from foreign sources, this is equivalent to a 7% tax on revenue that is payable to the Saudis, et al.
So, energy efficiency would improve one of the worst culprits of what is driving our trade deficit, which on the bigger scale would serve to reduce the need for perpetual borrowing and indebtedness.
Given the finite rate at which oil can be extracted, oil prices will inevitably continue higher and higher as they have over the past few decades. The oil price shock of last summer is taste of things to come, and investments made in these technologies NOW also serve to create a potential export industry in future decades... which in turn helps offset the trade deficit, and reduces the need for borrowing from abroad.
Additionally, periods of economic deflation are great times to build infrastructure, because commodity prices and labor unit prices are low, so infrastructure projects can be completed at a discount price. Again, if the government is really intent o spending money, then this might be a great time to invest in energy efficiency infrastructure.... nuclear power plants, and a modern rail system to transport goods and people would be excellent choices IMHO.
Our national business model has, for decades, been one of consuming more wealth that we create. This makes borrowing an inevitability, well either that or our currency will continually devalue. This can be broken if the trade deficit and current account are uprighted.
Unfortunately, we've probably already reached a break point where these decisions won't be made proactively by the government, and instead the market will be forcing these decisions for us... which can get messy. I sense the US and China will collectively be in, what economists refer to, as a "race to the bottom".