Another vote for the accountability involved in keeping credit cards. I use mint.com, which I highly recommend, to track all my balances & spending. I use credit cards for almost everything, but I check the balance every week or so, and categorize all my purchases so I can track where my money is going.
I also pay the credit cards off multiple times each month, especially if I've just made a big purchase. (I'm plowing through student loans right now, and my financing company allows me to make extra payments by credit card. Every couple weeks, I make a $1k payment, and then a couple days later, go pay off that credit card. $10 a pop in points for doing it that way!) I keep a few different cards - one is my oldest account, so I keep it for credit score purposes. It gets a single charge every month, and is set to auto-pay in full. Then I have the card I get most of my points on, and then finally, the ol' Amazon card, for Amazon points.
Mint makes it so easy to see where my money is going, and it provides a great snapshot of all my investments & other balances, too. The only way I would ever give up credit cards is if I suddenly found myself with a real spending problem (unlikely, lol) or if I needed to get rid of my paper trail, haha.