Here's another point to think about - book a RTW, and your ticket will be totally inflexible once you flown the first flight.

Book a series of one-way flights and you'll be able to change dates etc for any leg at any point, as long as availability is there.

Given that BMI is quite lenient in the definition of stop-overs as well, as you can see from reading the 'please post your redemptions' thread, and a RTW ticket seems bad value and inflexible.

By the way, why just one credit card?! You can easily get two and potentially more.