When I was younger, I vowed that I would be the one person in America who would go through life without a credit card. After all, why would I try to buy something that I didn't have the money to pay for?
As a joke, I filled out a credit card application when I was in grad school, insisting that I had an income of $0 per year, and no job (which was essentially true). And somehow, that was good enough to land me a platinum card with a $5,000 credit limit. I thought I would never use it...but that changed when I took a road trip to Vegas with some friends, and no one had any cash to pay for gas.
Now, I use my credit card to pay for almost everything because I appreciate the records that the credit card company maintains. I can easily go online and see what I've been spending money on, without having to dig through a bunch of receipts. As long as you can pay off the balance in full every month, credit cards can be useful tools; they make shopping online much easier, and they are essential for dealing with the occasional monetary emergency. You just want to avoid leaving a balance on your card. If that sounds like you, you might want to check out this site, where they discuss which cards offer the best rewards:
http://www.creditcardgoodies.com/
Carl: Congratulations! I remember the feeling I got when I was debt-free for the first time (I think that was 2002 or 2003, when I paid off the last of my student loans). It was tremendously liberating. I've been debt-free since then, and don't see why I shouldn't continue that way. The only thing that might change that is if I decide to get a house someday, but hopefully I can save up enough money to pay cash for it (although I might have to wait until I'm 55 to do so).
jb: The three main credit agencies in America are required by law to provide you with a free copy of your credit report once a year. Go here, and walk through the steps:
https://www.annualcreditreport.com/cra/index.jsp
Personally, I space them out every four months (I get my TransUnion report in March, Experian in July, and Equifax in November), but you may choose to get them all at once. If you see any inaccuracies on one credit report, it might be a good idea to get the others to see if they have the same problem, and get them all corrected at the same time. Your FICO score, though, is not free, and the credit scores that the credit bureaus try to sell you with your free credit report are not the true FICO scores that a lender would see. The only way to see your actual FICO score is to buy it from Fair Isaac (http://www.fairisaac.com/fairisaac).
All: If your employer offers 401(k) or 403(b) matching, make sure you at least put in enough money to get the maximum employer match. After all, why should you turn down free money? After that, your money would probably be better placed in a Roth IRA. You put in post-tax dollars, but that money is NEVER TAXED AGAIN. In most cases, that ends up being a better deal. You can read more about Roth IRAs here:
http://fairmark.com/rothira/index.htm
For my case, my employer matches the first 6% of my 401(k) contribution, dollar-for-dollar, so I put 6% into my 401(k). I put in my contributory maximum into my Roth IRA. I haven't been putting any more money into my retirement accounts for two reasons: (1) the US tax brackets are at historical lows, so it's very possible that my retirement tax bracket might be higher than my current tax bracket; and (2) I am seriously thinking about leaving the country for other opportunities in the next few years, and I don't know how the tax codes (both US and foreign) would handle money in a US retirement account. GoldfishX?