inheritance tax questions

Hello.  I am new to this- although I wish I had seen it a couple of years ago when I was first moving to England!,
I am an American married to a British citizen and living/working in England (expecting our first baby in April!).  I am about to apply for my ILR next month.  I still have bank accounts and investments in the US, that use my parents' address as my home address.  We expect to be moving back to the US in a few years or so, to be closer to my family, at which time my husband will have to apply for a green card etc.
In August when we were visiting in the US, we met with an accountant to have a preliminary talk about a Will, and through our conversation with her, she suggested it may not be a good idea for me to obtain dual citizenship. This is because  I would always be subject to UK taxes, including inheritance tax, even if we were living in the US.
I am reluctant to give up my opportunity next year to apply for citizenship, for if we ever do move back to the UK then we will have to go through the whole  immigration thing again.  But, if as my accountant suggested (but she did profess she is not an expert on UK tax law), it will be a huge issue, then I have to heed the advice.  Does anyone have any specific knowledge or experience?

Thank you

As far as income tax goes the US is the only country in the world that taxes its citizens if they are not resident.

I believe that you would need to be living in the UK for the inheritance tax to be in effect. 

And, not that I would advocate breaking any laws, but if they did try to tax you if you aren't planning on returning how would they ever know?  The UK does not require non-resident citizens to submit tax returns.  So if you inherited and moved back then you would need to declare it, but if you just stayed in the US then you should be fine. 

If you leave the UK and become resident in the US you won't be liable for UK taxes unless you have assets or income in the UK. The UK does not tax on the basis of citizenship as the US does. For example I'm a UK citizen and I've lived in the US for 25 years and I've never paid tax in the UK.

Until/unless the coalition changes the law, liability to UK inheritance tax (IHT) is based entirely on domicile.  Residence has no relevance at all.

Thus UK domiciliaries are always subject to UK IHT for as long as someone remains UK domiciled.

A little light reading for those interested. Take note of 'Deemed Domicile'.

http://www.hmrc.gov.uk/cto/customerguide/page20.htm

Thanks for the responses. There are so many  things to think about. I guess for now  I will stick with worrying about my set(m)  visa appointment in a few weeks, and then the birth of our first baby. After that I can worry about citizenship!
Thanks