OK I'm scared been in Bangkok for a few days and it's so busy and full of seediness, but at the same time I am also enjoying myself!!
One tip I would give anyone is to buy a sim card at the airport because the international call charges are killing me! Just buy a pay as you go, and they all have unlimited 3g so you can use Skype.
If you are going to eat in Bangkok don't waste you money on restaurants, the street food is much better and very cheap! Just eat and run (that does not mean dine and dash... just grab a quick bite to eat).
I would recommend taking a day to visit the Buddhist temples they are so peaceful and I have never seen architecture and culture similar. I was amazed with the experience!
Make sure you also get a night out clubbing... like a local... it's lots of fun and the people are so friendly and welcoming. One club we visited was the 808 and it was really cool!
And not to be too seedy even if (like me) your not their for the exotic offerings of Bangkok just go and take a look around the seedy areas... It's something you have to see! A real eye opener!