UK State Pension vs. Social Security

Should keep in mind, the state pension isn't the only state aid to pensioners - pensioners are eligible for a lot of other benefits (winter fuel, council tax, housing, tax credit, etc..).

The biggest difference to the US is that seniors in the UK typically won't be paying the equivalent of Medicare supplemental premiums and potentially large copayments/deductibles. Fidelity recently estimated these out of pocket expenses to average around $240k:

http://content.members.fidelity.com/Inside_Fidelity/fullStory/1,,7692,00.html

?? I understood that Medicare was not applicable overseas. You can collect your SS but cannot use Medicare except in the US. Do you mean it can serve as a fall-back should one return to the US to live?

Yes - I am a US Citizen (dual citizen) but my current plan is to return to the UK to live before I reach the age of 65.  However, I value my Medicare coverage which will kick in at age 65, and plan to pay the (approx) $100 per month for medicare Part B.  This will allow me (a) to spend as many months as I choose in the US visiting family etc, without having to purchase travel insurance, (b) visit the US for medical care if I choose, and (c) keep my options open if I change my mind and decide to return to the USA to live.

In the UK, you can make voluntary National Insurance contributions for any 'missing'  years to ensure better level of state pension should you return to the UK:

http://www.hmrc.gov.uk/ni/volcontr/basics.htm

To do this, I would enlist an accountant to advise you on how to do this.

http://www.icaew.com

You can also request a state pension forecast:

http://www.direct.gov.uk/en/pensionsandretirementplanning/statepension/statepensionforecast/dg_10014008

I also recommend Alvin Hall's Your Money or Your Life to help with financial planning from a UK perspective.