Tashkent is a nice city to visit - Uzbekistan has some economic development here, far from the traditions of the East and very touristy cities of the West.
Khiva is a small, fortified town located in the middle of the Uzbek desert. The town is an open-air museum with an enormous number of Islamic religious monuments that are open to visitors.
Bukhara is considered to be the holiest city in Central Asia. It's a key stop on a trip to Uzbekistan between mosques, madrassas (Islamic schools), and even mausoleums that have been here for thousands of years.
Shakhrisabz is authentic! I really enjoyed walking around here. The architectural heritage has not yet been renovated and it is far from the tourist crowds.
Like the rest of the Ferghana Valley, Kokand is not a town that attracts a lot of tourists; nonetheless, a day spent there can be full of pleasant surprises.
The country's second city, Osh, has retained relatively little of its three millennia of history, but it nonetheless remains a pleasant place for a brief stopover.
The appeal of Nukus as a destination boils down to the Savitsky Karakalpakstan State Museum of Art, which - for what it's worth - is absolutely fantastic. Otherwise... there's not much else.