Congrats Tom yes the 1.4 converter is often money well spent as the results can be very good, and could save the possible extra expenditure of a telephoto lens that would cost considerably more. The loss of 1 stop seems to be the key the x2 I  have found is not worth the expense as the loss of a further stop makes them only suitable more often than not to be tripod only.. And very very good light  required to get anything decent..

Danny O'Byrne  http://www.digitalartzone.co.uk/

"All the technique in the world doesn't compensate for the inability to notice" Eliott Erwitt