I love Bangkok. I live in a very small city, so I love to get to BKK for shopping and craziness.
Here are my tips (from many many trips there):
1. Chatuchuk (Weekend) Market. Take the sky train there (to Mochit). Only open on weekends. Its amaaaaazing, best market ever I am sure. Try go in the morning as it gets so hot and busy there.
2. MBK at Siam/National Stadium on the BTS (sky train). You can get everything you need, plus lots more. Computer stuff, phone, shoes, bags, clothes, also has movie theatre.
3. Phontip Plaza. This is like 5 floors of computers and electronics.
4. Bed Supperclub in Suhkamvit (maybe soi 11?) is cool. Kind of all white space ship like club. Go before 10pm or there is a cover charge.
Silom is pretty good for going out at night too.
DON’T encourage the people with the elephants in the city. Its soooo cruel. I saw one this weekend and he was crying, poor little elephant. And I hear they drug them. Yell ‘mai dee’ or something at the elephant people (‘not good!). If anyone Thai reads this, can you tell me how to say “You are cruel, you won’t get merit” please?