John Thorley,
I'm not sure your IFA gave you very good (or at least complete) advice when he advised you not to sell in Spring 2008 if you simply wanted to protect yourself from falling equity values. It's only when you draw your cash out of the ISA that you lose the tax-free 'wrapper' but there was nothing to stop you selling your shares and reinvesting the proceeds in, say, corporate bonds or Gilts (in fact, you would have done rather well).
In terms of the original question, I have to say it is something I've asked myself on several occasions as many people (myself included at the moment) simply lock capital away for years, never draw on it and then lose 40% of it to the taxman when they die. I tend to treat it as a 'rainy day' fund but I'm determined to spend some of it before I die or what's the point?!