Wat Bhudaisawan is near where my friends grew up. It is a very quite place as not to many people visit the Temple. It is a little difficult to get to as it is not in the main part of the island. You can get here by taking the bridge on at the western end of Ayuthaya or by taking a small boat across the river a a couple hundred yards upriver from the temple. There is a small school near by which if you happen to be passing by is a great time to talk with the kids as they love to practice their English!
Wat Phra Si Sanphet
Arguably the most impressive of all the sites in Ayuthaya - it was certainly the biggest temple in its time, and was used as the royal temple. The three central chedi contribute to the identification of 'Ayuthayan' style.
To reach it, continue heading west from the Ratburana, past the lake and through the park (20 minutes walk as long as you don't end up on one of the lakeside paths which simply lead to a deadend at the water's edge, resulting in doubling back on yourself)
It is common to see people bringing or buying flowers to offer at the Buddhist temples - along with money offerings etc.
Also they adorn the temples with garlands of fresh flwoers, and also pots of them. Some are magnificently created.
Wat Phu Khao Thong
The Wat Phu Khao Thong or "Temple of the Golden Mountain" is located a couple of kms to the north of town.
This massive buiding was built originally in the14th century but it has been enlarged in the following centuries. The huge chedi is probably the highest in Ayuthaya: 80 mt.
River boat to Ayutthaya
A good way to take in the sights of Ayutthaya would be to take a day tour. You go there by tour bus and return by river boat, which will drop you off at the Riverside Plaza pier next to the Orchid Sheraton Hotel.
The journey back to Bangkok takes about 75 minutes. Along the way, you can see no less than 50 temples and cathedrals, including the famous Grand Palace. You will also see stilt houses and how the Thai villagers go about their daily lives by the Chao Phrya River.