I visited this WHS in November 2016. It was part of my personal Top 100 list and it didn't disappoint. Perhaps it isn't as iconic as Angkor Wat or Bagan but it is one of those temple sites which in my opinion deserves at least 2-3 days to take in.
The most important temples are those of Virupaksha (still in use) just next to Hampi bazaar and Vittala which is quite a distance away. The latter temple houses the famous elephant-drawn chariot and it shouldn't be missed. It is also one of the few temples/sites requiring an entry ticket. For photography Vittala Temple is best left for the afternoon while Virupaksha Temple is ideal for morning light (especially the view from Hemakuta Hill.
The royal enclosure and the Zanana enclosure with the elephant stables (truly unique!), the queen's bath, the step well and the lotus mahal are also worth visiting. These are pretty much the most visited sites in Hampi. Two very impressive temples worth mentioning for their intricate carvings are the Mahanavami Dibba and Hazarama Temples (my personal favourites).
During the last day of my visit, Hampi was converted into an enormous festival centre for the Vijaya Utsav Festival. I enjoyed the colourful costumes and Karnataka dancers and musicians but more attention must be paid to avoid any damage to the site by the lighting equipment, the huge crowds and the unimaginable amount of litter generated by this event.
All in all, I had a great time in Hampi and I'd rank it as one of India's top WHS.