Preah Pithu is a group of five structures almost hidden away north of the Kleangs and east of the Terrace of the Leper King. None of the temples are especially large or monumental, nor have they been restored at all, but they can be quite interesting and you are almost guaranteed to have them to yourself.
Map by Ricardo.fabris, used under Creative Commons license.
The five structures are simply known as "T", "U", "V", "X" and "Y". "T" and "U" are built in a line very close to each other. Both have enclosing walls. North of these two, "V" is a spectacular tumbled-down ruin, with the remains of a long terrace stretching out to the west. Just a bit further north of this, temple "Y" is the smallest, sitting atop a small man-made hill. There's not much left of this structure, but the western end does still have some beautiful carvings on and around the false door.
The ruins of the Preah Pithu group in the heart of Angkor Thom.
Behind (west of) this group of four, on a slightly elevated platform, is the largest of the group, temple "X". A long terrace extends to the east of the main structure. "X" is a Buddhist temple, or at least was converted for use as one at some point.