It depends on where you are going.

The PASMO and Suica cards are interchangeable in the Tokyo-Yokohama area, but the Suica cards can be used in other cities for local transportation as well. Buy Suica at JR stations and PASMO at subway and private rail stations.

Now if you are going to be only in the Tokyo area, you should get a refund on your JR Pass, since you will never use up its full value. Just get a Suica or PASMO and use it for convenience (no need to buy individual tickets), load it with, say, ¥10,000, and use it for all your transportation, trains or subways, in the Tokyo area.

Note that the JR Pass is NOT valid on the subways or private rail lines.

If you are going to make a roundtrip between Tokyo and Kyoto or the equivalent distance, then the seven-day JR Pass is worth the money.

We really do need to make this information a separate stickie.