Manali is one of the best hill stations in India with awesome views of the Himalayas. Stay at Manali Ashok coz u get a great view of the mountains from here. The rooms and service is also good. It is best to drive down from Delhi/Chandigarh to Manali. The drive is great. It takes 12 hours to reach Manali from Delhi and that includes an hours break for lunch.
Definately go to Rohtang pass to play in the snow. People generally leave in the morning and start coming back by 3 pm. But i’d advise you to leave at 1-30 pm from Manali so that u can reach Rohtang by 2-30. The advantage is that by this time more of the snow on the road has melted and so u can drive further up and spot a virgin slope for urself. It is good fun to climb the slope and then slide down it. Take heavy wollens when you go up coz if you happen to get wet in the snow and if by chance the sun is hidden by the clouds, then it gets very very chilly. Snow shoes (gumboots) can be rented while on the way to Rohtang. Do try the white water rafting. u just have to take the experience.
Stay 4 days in Manali and relax there. Spend two 1/2 days at Rohtang (u go once and u wanna go back a second time coz it is so much fun there), 1 day for rafting and on 1 day you can spend some time in the market and see the Hadimba Devi temple which is very closeby. For food there is a Sher-e-Punjab in the market area. It is damn good. Best time to go is mid-april (u will be able to go only 1/2 way up to Rohtang pass coz the road will be covered with a few feet of ice) .... If you want to go to the top of Rohtang then you will have to visit manali in June. But it can get really hot in Manali at that time and you don’t really get the feel of a hill station then.
The taxi union in Manali is very organised. If you need a vehicle you can just call the taxi stand and the guy will come to pick you up from the hotel in the next couple of minutes. Very convinient. But it is advisable to have your own full time car/taxi with you.