Its estimated that only 1/2 of the population actually has a will. So how important is it to have a will? It depends. (How's that for an answer? Kind of what you'd expect from an attorney.)
One key element is that if you have minor children, a will can provide significant direction on who takes responsibility for your kids and how your assets are handled for them. If you don't provide that direction, the courts and family members are left trying to sort out the options, and quite possibly resulting in disputes. (And we know who wins if there are disputes - lawyers.)
Another key element as to whether you need a will depends on how your assets are owned. You can own assets jointly with another person, in which case they may pass automatically to that joint owner. Or you can have a named beneficiary (like an insurance policy) in which that asset passes automatically to a named person. Under either of those scenarios, it doesn't matter if you have a will or not, as those assets, which may be all of your assets, will pass to those individuals. However, while you may be able to get by without a will and save a few hundred dollars in attorney fees, but is that really the right answer for your legacy? What if your kids are minors? What if your surviving spouse gets re-married? Do you want to have control over what happens to your wealth?
These are just a couple of the issues to think about when determining the basic question of whether you need a will. The quick answer is that most people need a will of some variety. Contact an experienced estate planning attorney for additional information as to your personal situation.