VS 2010 - Custom Currency / Decimal Format

I have searched and found various methods for formatting as a string decimal values but cant fine one which covers all my needs. I have to display a decimal value (a financial money figure) i.e. 2500.75

However I do not require any leading currency symbol such as $ or £ and the main point I am struggling with is that when the value has no value after the decimal do not display zeros. I thought

Code:
.ToString(".##")

was meeting my requirements initiall but then realized if someone put the value 7.4 in it was displayed as 7.4 when it should be displayed as 7.40.

I have also tried

Code:
<%# String.Format("{0:0.##}", DataBinder.Eval(Container.DataItem, "Amount"))%>

But this seems to have no effect at all.

And in addition

Code:
<%# String.Format("{0:0.C}", DataBinder.Eval(Container.DataItem, "Amount"))%>

Always displays the two decimals even when zero.