It has very little to do with credit scores, MBNA shoved my interest rate up to 34% without informing me! no change in my credit score. Fortunately here in UK we have pretty good consumer credit laws, I challenged MBNA to produce a copy of my consumer credit agreement under those laws (They have 12 days to do so), they failed, and now i've legally disclaimed $9000 of debt, and they are legally barred from attempting to recover it!
Thats why you guys (US) need a consumer protection agency!
Who cares what the interest rate is? They could charge 10,000% and I wouldn't care. I always pay my bill in full the day I receive it, so I pay ZERO interest. I also get 1% back on all of my purchases, so I use my credit card for everything.
The rate could be 0.25% and still not many will be spending much money. The economy is on the verge of collapsing and no one will be buying big items. Only food stores who accept credit card charges may have some small business!