I would personally recommend Himachal Pradesh. You can visit places like Shimla, Kulu & Manali and many more. Plan for a night journey to Shimla from New Delhi. From Shimla book a vehicle and travel by road to Manali. You can enjoy the scenic beauty and reach your destination and I am sure you won't regret. Based on your budget you can add up Dalhousie, Kasauli and while returning you can have a stay at Chandigarh. Happy traveling.
Hi Manoj, Where natural beauty is concerned, Uttarakhand certainly has the upper hand. The state is spectacularly beautiful and there are few areas in Himachal than can match what Uttarakhand has to offer. Large areas of the state are still unexplored and out of bounds for civilians due to inner line restrictions that are very strict in Uttarakhand. From one of the highest Shiva Temples in the world (Tungnath) to the most beautiful of all the high altitude meadows (Dayara Bugyal) to the spectacular Valley of Flowers and the Highest Gurudwara in the world (Hemkunt Sahib) the state offers so much of natural beauty to a visitor which is unparalleled in the world. While Uttarakhand retains a lot of its unspoiled beauty and ruggedness, Himachal has lost it to development. Overall, I think when comparing the two, one has to keep in mind which parameters matter more. I like Uttarakhand and love it for its unspoiled beauty the simplicity of living and the fact that it is not expensive to live here.