I can't really see a trend right now, and feel that (at least in the US) we'll need to get to more "normal" levels of unemployment and economic growth before we can truly see how fiscal habits have changed. This is why I think things are up in the air:
People I see that make a lot of money and previously had out of control spending, generally still have out of control spending because they can afford it.
People that don't have high incomes (including college students) and those that have lost their jobs (because they have to) are much more conscious of spending habits and budgeting.
Kids that are high school age and younger that I encounter seem to be just as materialistic as ever. (i.e. "Have" to have iPhones even if their family is struggling to make ends meet, etc.)
If the middle group is larger than the high-wage earners and materialistic kids, habits of Americans will get better over the next generation, but if it is smaller, they will stay the same or get worse.