Itinerary Check - Rail Pass or Not?

I am coming to Japan for the first time in March2008. We will land at Narita Airport at around 9am will catch the train into Tokyo and plan to stay 4nights in Tokyo seeing local sights, we will then travel out to Hakuba to go skiing by train and stay there for 8nights, after that we plan to catch the train down to Osaka for 4 nights, probably spending a day in Kyoto (probably an organised trip but potentially using the train) we will then travel back from Osaka to Narita Airport (17 days in total) My question is should we buy a JR RailPass (im aware we will need to use Hikari rather than Nozomi trains where applicable) for this trip, if so should I pay out for the 21day version (57,700yen) or opt for the 14 day version and start it 3 days into the trip (so we use this for the bulk of the long distance travel) We would then need to separatly purchase a ticket from Narita Airport to Tokyo when we first arrive and some sort of ticket to allow us to travel around Tokyo for the days we will stay there. Any opinions on which option to go for? and if we do opt for the Rail Pass is everything I am planning to do covered on it? Thanks for you help. Steve

If you look up fares, you will find the following:
Tokyo-Hakuba by train: about 8000 Yen
Hakuba-Osaka by train (via Nagoya): about 11,000 Yen
Osaka-Narita by train: about 16,000 Yen

Conclusion: regular tickets cost about the same as a 7-day Japan Rail Pass for the last part of your trip.

An alternative would be to consider flying from Osaka to Narita Airport. There are a few direct flights from Osaka's Itami Airport. About domestic flights:
http://www.japan-guide.com/e/e2364.html

Or even better: leave Japan through Osaka's Kansai Airport.