We discovered its beauty by utter accident - coming back by car from Sicily we wanted to avoid well known route through Tuscany so we took direction towards east. And that paid off splendidly...
Now, Umbria is totally different than its more noble sister - mountainous rather than hilly, covered in forests rather than vineyards; wilder, calmer and much more probable to get lost in. The road winds through valleys offering rewarding views on little unknown towns and fertile slopes. Locals are much more local and Italian and you don't feel pressure on being a good, buying tourist .
Two spots we loved most describe well Umbria's originality. Marmore Falls depict its wilderness, virginity and astounding charm. Hidden in forests, 7km from the town of Terni (we had problems navigating chaotically signed roads) present a monument of ancient Roman architecture - designed as water system solving local problems it became an inspiration for artists and favorite vacation spot for the nobles. Today, 165 m long cascade is a wonderful trekking route enabling you to feel the power of water masses.
You can approach the waterfalls from up and down - either way, footpath will take you through terraces, caves and best sightseeing points. And it gets very wet sometimes! Entrance fee: 7 euros; open during season from 10 AM - 1 PM and from 3 PM - 10 PM.
Second jewel was a town Spoletto, 30 km north of Terni - a quiet medieval city born as a fortress due to amazing views (check small hill above the town - the Albornoziana fortress) today it offers peace, Italian pride and best narrow winding streets. Main square is just lovely in its modesty and the Duomo of S. Maria Assunta pleasantly fulfills the impression. There are naturally many more churches you will want roam around but don't miss Roman amphitheater serving now as archeological museum.
Trattoria la Toretta and Osteria dell'Enoteca Spoleto are among best restaurants to eat at. And ice cream stands are just splendid!