Taking the four hour train ride from Bukhara to Tashkent on the fast train is a great alternative to the frenetic shared taxis in Uzbekistan. The first train leaves at 04:55 and arrives at around 09:00 in Tashkent.
In Bukhara, the train station is about 13 kms outside of the city at Map Location: 39.722241, 64.548588 . Taxis charge between 30k and 50k depending on day or night and the negotiating skill of the passenger. A 4 am taxi will cost the maximum amount and can be arranged by the hotel staff the night before.
In Tashkent, the train station is in the city at Map Location: 39.7728, 64.421545 . The entrance to the 'Toshkent' metro/subway station is right in front of the train station.