Bukhara is one of the most famous cities on the ancient Silk Road. Samarkand is maybe a bit more famous, but Bukhara wins hands down when it comes to atmosphere. This city is alive!
The old part of town offers an incredible number of sights. The first or last stop of any visit should be the Lab-i-Hauz, a great place to relax, sit, drink tea (or something stronger) and wait for the fountains to start again.
Seen from the Lab-i-Hauz the Ark or Citadel is at the other end of town. Between those two are magnificent Koranic schools, impressive mosques and a big tall minaret with a history that will make you shiver...
You should also not miss out on visiting the newer part of the city to see how Uzbekistan is lived nowadays, rather than only concentrating on its history.
Most of the main historical sights in Bukhara are located together. Try to stay in one of the Bed and Breakfast hotels located near to Lyabi Hauz rather than staying in one of the rather impersonal big hotels. Also, staying in a smaller family-run hotel means that the income goes direct to the local people, rather than to some large company