One of the most effective wealth transfer strategies in recent years have been Family Limited Partnerships and Family Limited Liability Companies.  Essentially, these entities have significant restrictions on voting and transfer rights which allows them to have deep discounts in their value.  Then the equity interests are gifted or sold equity interests to family members at a significant discount.  This effectively transfers out value at discounted rates.  For well off families in places like Wilton CT or Bedford NY, this can be an effective technique.

However, the IRS is now proposing new regulations under IRC §2704(b)(4) which may drastically limit the ability to use this technique.