For some reasons, I appreciated Angkor Wat better in the afternoon - at sunset - than during the popular and obligatory sunrise visit where all tourists to Angkor are expected start their journeys with. In either case, it was such a delight to see that Angkor still receives a lot of visitors even during off peak seasons!
Of all the many temples and ensembles I have seen, I really cherished my experience at Bayon, the 'almost secret' ground alleys of the Terrace of the Leper King, and Prasat Kravan - the last two only receiving a handful of tourists. Prasat Kravan (which has a twin temple as well in Takeo province - the Prasat Neang Khmau) is probably one of the under-appreciated temples in Angkor, but I personally think that it is one of the most unique - the murals of the central tower was indeed a find, and it has a history much older than most.
Unfortunately, I never got to feel the amazement that people usually claim to have experienced at Sras Srang (the royal bath) as it was under renovation when I last visited. Aside from the enigmatic temples in the area, I find the water system - barays and the canals - to be just as interesting and intriguing.
I could only agree that Angkor is indeed one of the best cultural wonders (if not the best) and an incredible engineering feat the world has to offer. It's definitely a topnotcher.
TIP 1: I always find that watching a performance of the Royal Cambodian Ballet (Apsara Dance and Cultural Shows) complements well one's visit to Angkor.
TIP 2: If I were to recommend, be sure to see and at least spend some time exploring Bayon, the terraces, Ta Prohm, Pre Rup, Banteay Srei, Sras Srang (after the repairs!), Prasat Kravan, Neak Pean, and Angkor Wat.