From Narita Airport to Ginza

Can you please advice me what is easiest and cheapest way to go to Mercure Ginza Hotel from Narita Airport?

The cheapest and one of the easiest ways is taking the Keisei Limited Express from the airport to Higashi-Ginza Station (easy transfer at Aoto Station along the way) and then walk to the hotel (less than 5 minutes).

The train ride takes 90 minutes and costs 1100 yen.

Thank you Uji for the advice. Is there any unlimited day pass which you think is good for me to buy so that I can tour around Central Tokyo for 4 days? I will change to my JR pass (for next 7 days) to go Kyoto and Osaka; afterwhich to come back to Tokyo for my last 2 days stay. I am staying in Japan for total of 11 days.

I recommend to use a Suica or Pasmo prepaid card to get around Tokyo:
http://www.japan-guide.com/e/e2359_002.html

For most people it comes cheaper than day passes. If you are interested in day passes, after all, e.g. on a particularly busy day, see the following page for a list:
http://www.japan-guide.com/e/e2017.html

I caught a train from the airport to Tokyo station and then caught a taxi to Mercure Ginza. Taxi fare was only 600 Yen, which was quite reasonable. The hotel is only 5-10 minute drive from the station.

You mean I could take a JR Narita Express train (or what other rail/subway?) to Tokyo station and hop in a taxi for 600 Yen?! Can you remember how much is the fare for the JR train? I have heard so much of hefty taxi fares in Tokyo but if it was 600 Yen, and if there is not much traffic congestion, this sounds like a good alternative to me, thanks Rowena :)

The hotel is 1.5 kilometers from Tokyo Station. By taxi, you will likely to have to pay just the base fare, which, depending on the taxi, is between around 600 and 800 yen. But the Narita Express costs 3000 yen (1500 yen if you buy it in combination with a 200 yen Suica prepaid card - see NEX&Suica package)!

Thanks Uji :) for all the wonderful information and tips!