1. Bankruptcy.
A bankruptcy will stay on your report longer than other items (10 years instead of 7), and in may cases is the primary concern of interested parties. For instance, when you apply for an apartment, many times the landlord will be interested if you have a bankruptcy on your record at all. On the other hand, a very recent bankruptcy, damaging as it may be, can also mean you don't have any other debts and therefore are less of a risk to a potential lender. Don't count on it, though.

2. Charge off.
When a company decided they just aren't going to get their money back from you, generally after about 6 months, they write your account off for tax purposes. This doesn't mean you don't owe the money anymore or that they can't do nasty things to you to try to get it; it's just an accounting term, and trust me, it's a BAD thing to have on your record.

3. Collection agency.
After the charge off, the company may use an in-house or third party collection agency to try to recover whatever amount they can from you. There's no need to tell you how bad these look on your report, and you should try to clean these up in any way you can, by paying them off in exchange for having the agencies remove the entry, or paying them off to change the entry to at least show "Paid Satisfied."

4. Tax lien.
If you fail to pay your taxes, income, property, or almost anything, the government may make your life miserable to get the money from you. One of these is to secure a lien against any property you own, either personal or real. The government then literally owns your house as either security to pay or to sell and get the money. As long as these remain unpaid, they can stay on your report for 15 years.

5. Foreclosure.
If you fail to keep up with your mortgage payments for a length of time, the bank may take your house away from you to sell it and recover the rest of their money. This is called foreclosure, and not only do you lose your home but you get a nice crappy credit score to boot! Nice, huh?