What to keep and what to toss

Toss Immediately

Credit Card Solicitations
Marketing materials included in bank and credit card statements

Throw out after one month or when you reconcile with a bill or bank statement

ATM receipts
Prospectus and other information about investments you are considering making (if you are not going to read them, toss immediately)
Receipts for purchases (assuming you're keeping them or there's no warranty)

Throw out after one year or when end-of-year consolidated statements come in and you have filed the taxes for that year:

Bank statements
Brokerage statements
Cell phone, cable, telephone, and Internet statements (except when deducting for work-related expenses)
Pay stubs
Social Security Statements
Utility Bills

Throw out after seven years (when no longer needed for tax purposes)

Child-care records
Flexible spending account documentation
401(k) and other retirement-plan year-end statements
IRA contributions
Purchase records for investments
Records of charitable donations
Records on houses you've sold
Tax returns and backup documentation

Keep as long as you have the underlying asset (such as a house or a car)

Insurance policies
Receipts for important purchases like technology, art, antiques, rugs, jewlery (or anything else you may need a rider on  your insurance policy to cover)
Receipts for renovations or other investments made in the property.
Titles
Warranty Papers

Keep forever in a safe or safe-deposit box; keep a second copy-if possible-in your attorney's office or another safe location off-premises:

Adoption papers
Appraisals
Birth certificates
Citzenship papers
Custody agreements
Deeds
Divorce papers
Financial aid documents
List of credit car numbers, bank and brokerage statements, and insurance policies, and toll-free contact information.
List of important contacts (lawyer, accountant, doctor, children, parents, etc)
Military records
Powers of attorney (medical and financial)

Intermittent upkeep

Every time you open a new account, take out a new insurance policy, or do something that requires record keeping, immediatly make a new folder.  Print a label, and figure out where the folder goes.  The first thing in the folder is the new contract you've signed so if you every have to refer to it you know exactly where to go.

Annual upkeep

Every year, after you've filed your taxes, remove last year's manila folders from the file box and place them in another set of hanging files in a filing cabinet or drawer.