Ah, I should be in BKK myself around that time, too.
Can't really offer much on hotels since I got a place there myself to bunk with. But, I wouldn't worry so much about getting around since BTS (LRT) and taxis are easy access. And taxis service are WAY better then it is here in MY.
Pratunam is a bit more like our own china town/chow kit. And it would prolly cater more for apparels. Chatuchak is rather squarish but in a big piece of land and its more of little stalls/shops in an open area (unless they changed it from I last went). You'll find all sorts of stuff there. Don't be expecting originals and designer labels though. And yes its very crowded, but not too complicated really unless you got a bad sense of direction

Pratunam MIGHT be the worst in terms of navigating your way around.
Best place to shop for cheap but branded clothes? Hmm, I'd say MBK (MahBoonKong). Its a mall which you can get to easily via public transport.
Malls aren't bad really, I'd say its worth going and theres a lot to choose with. Then again, I be a guy and I don't really shop

But if its your 1st time heading there, I'd really suggest going for the cultural feel, even if you aren't into it.
Best food for me usually is the small hawkers/stalls out on the streets. They are cheapER and always taste a lot better. Just watch out for hygiene though, some aren't too... sanitary. Only problem is they are harder to converse with the cook in what you want, so food courts/restaurants might be easier.
I don't believe I've been to a place where they accept RM. There are some that take in USD. But any shop or establishment that would take other currencies apart from the local ones usually would charge a crazy exchange rate, so I would advise against that. Theres plenty of money changers around there so just look around and see which has the better rate going for you. Banks don't have a better rate, but would be easier to deal with. You can change it here in MY too, the rate ~isn't~ that bad.
Have fun, worry less, absorb as much as you can.
Ah, forgot to mention that Chatuchak is weekend only. Might want to plan accordingly for that.
This post has been edited by vermins: Dec 22 2008, 04:23 PM