Cell Phone Is Definitely Useful
[QUOTE]Highly recommended having the cellphone.[/QUOTE]Plus one on the need for a cell phone. Get one with a keyboard to make it easier to send text messages. This is handy when you're in a loud bar and you need to text your mates (who are probably in another loud bar). Or when you've got your hands all over some hottie and you don't want to take a voice call. Also lots of the girls are more comfortable sending text messages than talking on the phone as it helps a little with the language barrier.
You can buy unlocked GSM cell phones on the Bay of E before you go. Older models are almost as cheap as they are in Thailand. You can buy a SIM card the same way. The advantage to buying the SIM card in advance is that you'll know your phone number before you start your trip. This is useful if you can't find your driver at the airport. (Although those people are masters at somehow finding you, even in the absence of real time communication.) And you can give your friends back home the number so they can reach you when you're on holiday. (If, in fact, you actually *want* them to reach you.)
If you can wait until you get to Thailand to buy your cell phone I recommend the MBK Center in Bangkok, where they have every conceivable cell phone for sale, plus SIM cards and airtime. You can even get vanity cell phone numbers if you think certain digits bring good luck. They can also unlock or jailbreak just about any phone ever made. In Pattaya the Tukcom Center has a good selection of cell phone stuff as well.
Bunky