After visiting a fair share of "Thailand Forums" one notices that newbies will often ask if they should go to Bangkok, Pattaya or both. They also usually want to know how long they should stay at each place - if they go to both.
As a seasoned traveler to Thailand for over 30 years, I tend to be a bit cynical and advise most to just go straight to Pattaya. But, there are arguments to be made to stop by and visit Bangkok for a few days too.
I have toned down my advice a bit and usually tell the newbie to visit Bangkok for 2 to 3 days at the beginning of his trip and then spend the rest of the 2 or 3 weeks in Pattaya. Everyone should see Bangkok at least once.
There is a lot to see in Bangkok if you can ever get to where you want to go. Traffic is usually moving along at a snail's pace and the meter in the taxi keeps ticking away. Walking around is hot and the streets are lined with vendors that block the sidewalk and will try any tactic to get you to stop and buy something from their stall. And, if you are walking around at night, you will have to watch out for the lady-boys and the muggers (as you would in almost any large city).
Once you suffer taxis and heat, there are numerous clubs, bars, and restaurants that would rival the best anywhere in the world. With prices being extremely low (despite the strengthening of the Baht), you can have a great night out on the town for a minimal amount of money.
Throw in inexpensive hotels, excellent shopping, and the friendliest people in the world, and you will have an experience unlike any you have ever had. Then, on your second visit to Thailand, you can just go straight to Pattaya.