First thing first
This is meant to be a tip for Foreigners traveling in Thailand, especially Bangkok. I've been reading this post on LifeHacker and I thought I could add a few things over that piece.
I'm a local, to be honest, being a tourist country meant that we are intended to rip off your money. The cost of living is very low compared to the US and Europe, so most of you will think stuff here at the touristy area are cheapo cheapo, you are dead wrong. You can get the same stuff at half the price if you shop at the non-touristy place meant for the local.
I'll begin my guide by adding a few tips and correction to that article on LifeHacker.
[TIP] If you've got one of those hotel room keycard that has to be inserted on a slot to activate the room electricity (featured in the article). Just take the keycard out of the keychain and leave it on 24/7, just make sure you don't lose the key.
Don't bring the laptop, unless you intend to work here. Though the US type power socket will work here, the AC voltage is different (Thailand: 220V, 50Hz). Most laptop chargers/adapters are compatible with Thailand's voltage (check the label). Consider investing your money in a universal socket adapter won't hurt.
As suggested in the article, you could bring a flash drive loaded with portable software (Firefox, Photoshop 7, etc), make sure that it is loaded with an antivirus. Recently there has been numerous outbreaks of trojan those spread through portable drives and instant messenger in Thailand.
[TIP] Some dodgy internet cafe will plant a keylogger in their machine, especially those in touristy area. Avoid them and check into the decent ones when you're doing a secure connection/transaction/whatever.
Internet Cafe are everywhere in Thailand! For the down the street ones they should've cost no more than 40 Baht/hour (standard price: 10-15 Baht). Don't use the ones who show "10 Baht/10 Min", they're seriously expensive for our taste (i.e. they rips you off). Nicer cafes include true internet cafe, located in major shopping malls (e.g. Siam Paragon).
Where to buy pirated stuff?
You could buy pirated software, music, movies practically anywhere in Thailand. Though I recommend these places, Thai people mainly shop there for Hardware and Software:
CDs will go for around 100-150 Baht, and DVDs will go for 200-300 Baht. Shop around the places, there will be shops those offer better bargain. Don't be worried if they offer you porn, it's virtually legal around there, just name your type (Thai, Japanese/Korean, Caucasian/Farang, etc).
Don't be surprised if they take at least 5-15 minutes to deliver your stuff, make sure you get a deposit slip if you were told to wait. On some day it will take particularly longer or they won't sell stuff because there will be *annouced* police raid.
Tuk-tuk may be the symbol of Thailand transportation, however, they weren't originally designed for tall caucasian (I'm 6" and I have trouble fitting in one). If you wish to have a hot, sweaty, greasy ride, be my guest (though you *must* try it once at least). They charge a fixed rate, negotiable sometimes.
Taxi is the best way to get around the city, take a newer ones (tuned down Toyota Corolla S/Altis). Generally the sky blue ones offer the best service. The meters will have an offset fare at 35 Baht and will slowly increase at 2 Baht per tick. Calling taxi from the airport will add 50 Baht to the metered price, always ask for a 50 baht receipt from the taxi desk.
[TIP] Fixed rate are for long distance trips only, generally 50 km+. For in town trips, ALWAYS ASK FOR "METER" FARE WHEN YOU WERE ABOUT TO GET ON, IF THEY ASK YOU FOR A FIXED RATE (NO METER), NOTE THE LICENSE PLATE NUMBER AND GET DOWN IMMEDIATELY.
The skytrain (BTS) and subway (MRT) are the most efficient and popular way to get around the city. Though the system is not as large as developed countries (Paris system has 21 lines lol), there are currently 2 lines of BTS and 1 line of MRT. They're very convinient, cheap, and fast.
Don't step over the yellow line when you're waiting for a BTS, or else you'll hear some angry whistles from the security guard. Let the people get down first then hop on.
Motorcycles are also great! Some of them will offer a decent helmet, but most wouldn't. Get ready for exciting rides, those riders know how to get around but won't guarantee your safety.