Any low tax jurisdictions would do. One of Facebook's founder gave up his US citizenship to move to Singapore to avoid US tax liabilities. However, US has exit tax to pay upon giving up the citizenship.

I agree Michael - that Form is the 8854.... Such a joy!!!!

There is a wide choice of low tax jurisdictions, so much will depend on lifestyle choices, succession laws and residency/citizenship rules.

The big question is how do you plan for a new residency/domicile status and obtaining another passport? You will need the other passport as soon as you complete the abandonment of your US citizenship.

As the previous correspondents have flagged, the US "exit tax" rules have the effect of triggering a deemed sale of all capital gains liable assets. There is a limited statutory exemption (circa $651K) and a deferral option (which accrues interest).

Some jurisdictions effectively "sell" residency with a passport entitlement (e.g., Dominica, St Kits & Nevis - possibly Antigua & Barbuda shortly). Others require 3-5 years permanent residence to obtain citizenship (e.g., Costa Rica, Belize).

If you are well-funded, and you get over the initial passport issues, Bermuda and Monaco can be very pleasant.