Be careful . . . be very, very careful. Double and triple-check with your bank in Taiwan if you want to use your ATM outisde of Taiwan.
From my experience, some banks will say you can, others will admit you cannot. I could not use my ChinaTrust ATM card nor my EnTie ATM card last year in Thailand. However, my Taiwanese friends could use their cards (from the same banks and others) to get cash without any problems.
Even if your bank assures you that you will be able to use the ATM card issued from their bank, it still might be good to have a back-up plan–i.e., cash or traveler’s checks.
Have a good and safe trip to Thailand. Please post some notes when you get back–I’d be curious to hear what the mood is like in Thailand after the recent disaster. Also, I’d like to know if the number of tourists is down–or are people continuing to travel to Thailand as before.