For overseas transactions go with Maybank credit cards as they currently have the lowest overseas conversion fee:

For MBB, you have two options:

1. If you pump at Petronas only then get the Maybank Petronas Visa Credit Card. 5X Treats Points at Petronas Station and on Weekends 8X TP for Petronas and Groceries.

2. If you pump at Petrol Stations that accept AMEX, e.g. Shell and Esso (Petron soon), then get Maybankard 2 Cards. The American Express credit card earns you 5X TP everyday PLUS 5% cash back fon Saturday and Sunday for any type of transaction. For overseas transactions, use the MBB 2 Visa or MasterCard as the conversion rate because the AMEX card is very high. And this MBB 2 Visa or MasterCard do earn you 1X TP if the even that the petrol station does not accept AMEX. Now, you may earn 5% with the AMEX on weekend for you overseas transactions with the AMEX but this is very tricky if you are doing online transactions and is not guaranteed.

For more info on overseas transactions click here to Credit Card Foreign Exchange Rate Thread

And if you do not mind having a card outside of CIMB, Maybank and Bank Islam, the OCBC Titanium MasterCard is a very good card to have as it earns you 5% cash back everyday for Petrol, Groceries, Dining, Utility Bills and Telco autodebit but the cash back is capped at RM50/month or RM1K spending. That's like maximum RM600 cash back a year.