I assume that to most people around here, marriage means חופה וקידושין.
A vast majority of people obtain a marriage license and get legally married.
In quite a few situations, especially if one can control the income flow/split between the couple, such as business owners and other situations, it is financially advantageous not to be married, but rather to file as two singles, a single and head of household once there's one child, and once there are two or more children two heads of household, splitting the dependents between the couple.
Furthermore, with the way the legal system currently defines marriage, I wouldn't want to have anything to do with it.
I have two family members who have followed my advice in recent years, and did not obtain a marriage license. It is working out quite well for them from a financial standpoint. They are protecting each other with life insurance, and I would suggest getting legally married closer to retirement age.
I found the financial benefits so compelling, that I researched and found out that one can get divorced in one day in NH. However, I did ask my mashpia, who advised me not to do so, saying that not getting "legally" married in the first place is different than getting "legally" divorced.
Obviously, some people must get legally married for immigration status, but if that is not an issue, how do people feel about being married בחופה וקידושין without being legally married in the eyes of state and federal law? Is there any legal or halachic problem?