Mick from Wilderness Trekking questions our choice of the Annapurna Circuit as one of the top 10 hikes in the world:
… road building and the inevitable changes with so much trekking traffic have taken their toll …
He suggests a number of terrific alternatives:
Sacred Tsum Valley – Nepal
Classic Manaslu Circuit – Nepal
Everest Base Camp – Nepal
Dolpo Traverse – Nepal
Mythical Nar & Phu – NepalMount Kailas Kora – Tibet
Remote Zanskar Traverse – India
Markha Valley – IndiaWild Lunana – Bhutan
Phubjikha Festivals – Bhutan
Mick’s company guides those great adventures. For example:
… Our Phubjhika Festivals trek combines exploration of many of Bhutan’s historic places of interest, including Taksang, or the Tigers Nest Monastery and coincides with perfectly preserved, ancient Buddhist Festivals.
Making use of a chain of comfortable Bhutanese style hotels, we travel with experienced, English speaking local guides who will be able to interpret our experiences and offer personal insights into this fascinating culture. No trip to Bhutan would be complete without a walk through the Himalayan mountains and our gentle three day trek in the Phubjhika Valley, home of the endangered ‘Black Necked Cranes’ will give us just enough time to relax into the Himalayan rhythm before visiting the annual Nyzer Dromchoe Festival. …
besthike.com 
That’s an excellent and helpful list. Note however, that many of those listed require special permits and “guides”, which means they are ideal for companies selling trips, but an annoying factor for those who just want to hike a good route.