Depending on how many days you plan to stay here, you might want to visit Pattaya city if you wish to cover many things Thai, but is short on time. There you can see what Thailand's night life is like by visiting Pattaya's Walking Street. You can also have your elephant ride there, and Jomtien beach is nice and it has areas that are not that touristy.
However, if it's ancient Thai architecture and history you are after, then Ayutthaya is the must-visit place, around 2 hours from Bangkok.
Ayutthaya is best visited by renting a van for a day, most times, you pay 1,500-2,000 baht for the van and the driver, and you pay for your own gas, which would probably be another 1,500 - 2,000, depending on how many temples and ruins you wish to visit.
Pattaya on the other hand, can be reached by air-conditioned public bus, and fare i think, is less than 200baht per person, and you can stay in very simple accommodations as low as 500 per night. Within Pattaya city, you can just walk, or take public transport (song thiew, aka the red truck) for only about 20 baht per ride.
Anyway, before i keep rambling on, tell us a bit more detail about what else you want to see and do here, then we'll give you more info.
Great that you find our site useful, and thanks also, Softrock, for responding promptly, to a kababayan's call for info.