They can make close combat attacks one square away.

They used to have a larger adjacency but it was changed with the FF starter. That made Hulkbuster's power useless.

For close combat purposes, they can attack from 2 squares away.

When the BN starter is released on May 12th, they are considered adjacent for close combat attacks up to 2 squares away. Thus, allowing for quake and such other wonderful powers to work.

ShadowMark is correct.
To explain a bit...

Prior to FF, the giant rules were simple. For movement and close combat, they were adjacent two squares away.

With FF, the giants were nerfed. They lost the two square adjacency across the board, BUT they could still make close combat attacks two squares away. Being able to attack someone with a close attack and being adjacent to a figure two squares away are not the same. There were quirky things which now did not work, like Flurry and Quake, as those powers still require adjacency.

When the new book comes out, it goes back to actual adjacency for close combat 2 away.