From a tax point of view it is worth waiting to 6 April because you will not have to include that on your 2010 tax return which is up to 5 April.
Natch. From a tax point of view it makes stuff all difference, save that you would have to complete another tax return.
If you are likely to purchase in excess of 50k of plant in the period to March 2011 (including all purchases to date) then you might wish to think a little harder.