Depends on where you're staying and your trade-off preferences (generally, time vs. convenience). I'm assuming that you may have a couple of suitcases that you can wheel.

If you're staying at a hotel that's right at a station served by a train (e.g., The Strings or one of the Princes @ Shinagawa, or one of the Tokyo or Ueno station hotels) then to me it's a no-brainer: you take the train. Extremely easy to do, and the departure/arrival times are a certainty: trains leave 2x/hour, and it takes about 60 mins to Tokyo staion, 70 mins to Shinagawa, 90 mins to Shinjuku stations.

If you're staying elsewhere, it becomes more complicated. The easiest choice is the airport limo bus: it will go from Narita to your hotel. The problem is that the buses run infrequently (once an hour, or even less frequently), they make make a stop or two before your hotel, and they get caught in Tokyo traffic. At the hour that you arrive, it can easily take 2-1/2 hours to get to a Shinagawa hotel -- and that's after you get on the bus. The alternative is to take the train to the nearest station, and then a taxi to your hotel.

Things get more complicated, as with the train (and maybe the bus, too) you can buy various combination packages that include travel on Tokyo subways and trains. My suggestion would be for you to be aware of these things, then make decisions much later. (Example: On my recent trip, I could have gotten one of those combos, and it would have saved me about $20 in local transportation. However, I would have missed the next airport train to get it done; I eschewed the $20 savings and got to my hotel right away.)

Tokyo MK and Tokyo Airporter are two very reliable transport options that aren't so so expensive in terms of convenience, comfort and speed.

basically four ways to get from NRT to Tokyo. The taxi or limo service mentioned by Kim costing anywhere from $250.00 to 350.00 US. Then there are the trains noteably the Keisei Super liner and the NEx Narita Express both costing 2800 to 3500 yen per person. The trains are nice if you don't have too much luggage and are staying near a train station. If you are not staying near a station they stop at then a taxi from the station to your hotel is the answer. Finally there is the airport limosine bus with door to door service from NRT to lots of hotels in Tokyo and just about all major train and bus stations. As Don says above its a little early to know which to use until you find out what hotel you will be in. Personally I like the limo bus because the hotels we stay at are on their schedule and the service is door to door. The porters take our luggage from us as we que in the bus line and load our luggage on for us as we board. When you get to the hotel your luggage is taken by the door person and the next time you see it is when the bell person is bringing it into your room I say bell person because a lot of bell hops are female in Japan. No tipping necessary.

The limo buses are also equipped with a sophisticated GPS systmes that tell them where the traffic jams are and they are able to re route around traffic if at all possible. The longest bus ride I can remember from NRT to our hotel in Shinjuku was on a Friday evening with heavy traffic that lasted 115 minutes......not to bad at all. It would have taken at least 90 minutes to Shinjuku station via the NEx then having to deal with the mazethat is Shinjuku station along with getting a taxi on a Friday evening put us at about the same time level with less transfering. Bottom line is when you know where your staying is the time to decide which mode of transport.

You can also heli into Tokyo but we'll save that option for the Kimball's

Aloha!

oh the limo bus will cost around 3000 to 3500 yen p/p depending on the distance. there are also limo bus and Tokyo metro pass deals. The trains also have a similar deal with the train tickets and a suica card. what is a suica card you ask?

http://www.japan-guide.com/e/e2359_002.html