The allocation of GST exemption to a transfer or to a trust excludes from the GST tax not only the amount of the transfer or trust assets equal to the amount of GST exemption allocated, but also all appreciation and income on that amount during the existence of the trust.

FORBES: Obama Estate Tax Budget Proposals

Irrevocable trusts enable individuals to avoid estate tax on more than the exemption equivalent amount of property.

FORBES: Estate Planning Overview and Objectives

Dynasty trusts push that generation-skipping tax exemption to the max, putting the exempted amount beyond the reach of estate taxes for the life of the trust.

WSJ: Tax Report: Dynasty Trusts Under Attack