My favorite temple was Ta Phrom.
We got there at about 7:15am (by bike!). The place was entirely ours: there were (maybe) 6 other people there and it was cool (in contrast to the afternoon’s humid/sticky/unbearable afternoon heat).
Unlike the other temples, restoration efforts did not remove the trees that had grown in and around the ruins. The result was a sensation of stumbling upon an ancient temple in desolation while walking through the jungle.
The “Tomb Raider” tree.