GTG
Striker
Regarding your question about a trip, without any doubt I would suggest you opt for Ayutthaya, which was the old capital, rather than a myth based upon a film shot in Sri Lanka, which is a post war construction.
I think that's a bit harsh! It's only the bridge itself that's a myth, the history of what went on in that region is very real and I think the cemeteries, the museums and the 'death railway' itself can form part of a very interesting and emotional trip. It's also one of the nicest areas of Thailand, imho, the Erawan falls is a particular favourite.
If you're stuck for time you can get some really good organised tours to the area which include a night or two spent on 'floating hotels' on the river.