How much is my good credit rating worth?

Hmmm.... I got a credit card application from Chase Manhattan offering me a "free" $25 gift card to Old Navy, Blockbuster, Bennigans, and 57 other establishments. Even better, there's no fee on the card, so as far as I can tell, I could sign up, be approved, get the $25 certificate, then a few months later cancel the card and be $25 ahead. The app is online at my chase platinum.com.

But it's not quite that simple, because your credit report is scored and one of the variables that's considered is how many credit cards you have, how many you've recently cancelled (imagine: you can clean up your act, cut up some credit cards, and have that count against you on your credit score. Weird), and how many you've applied for. So, the $25 might well adversely affect my credit rating, which would cost me a lot more than $25 in the long run.

Chase Manhattan doesn't say that - in fact, I've never seen a credit card application that says "warning: applying for too many credit cards may adversely affect your credit rating", but it'd be pretty nice if it did...