If you factor in the cost of the debt to pay for our military spending then I think that a reasonable estimate of our yearly defense spending is about $1.5 trillion.
The amount we spend on defense swamps other US government spending, including social programs. This is just my opinion, but I believe that we could keep our country relatively safe (compared to other countries) and spend far less money. The problem is basically banana republic style corruption: too much money is made by special interests for there to be any meaningful reform of military spending. The same comment is also true of other corporate interests like Wall Street, industrialized food production, pharmaceutical companies, insurance, etc. This is all enabled by total corporate control of the news media and shameful corruption in the lobbying industry and our federal government.
Fortunately, for most of us, life is still very good despite corruption of the world's "elite." Again, this is just my personal opinion: it is best to act in ways that help yourself, your family, and local community. Avoid doing business with large banks, preferring credit unions. Prefer buying food from local producers. Form or join local organizations for food distribution, computer clubs (promote open source solutions to help people use old PCs), and help with local school fund raising activities. Prefer to buy goods that are manufactured as close to where you live as possible.
Joy in life comes from our family and social interactions and in acting in service to others. A materialistic lifestyle is something that you have been conditioned to accept by lifetime exposure to media - try to resist the temptation to acquire material goods that you really don't need.
And, most of all:
Have a Merry Christmas and a Happy Hanukkah!