I just recieved a letter from Citibank who is increasing my APR from 9.9% to 16.99%. Should I opt-out?

i think the credit card has had it's day - mive default rates ( along with bank greed ) got us into this trouble so to avoid a repeat credit card companies and banks will be getting a lot lot tighter and removing credit lines earlier when debt amounts are more likely to be recovered sucessfully - it's time to be working on reducing that credit line you require from 6k to 0.