Hi Joe,
I am glad to hear you went with the 10mm Pentax XW. I was confident when recommending it that you would like it. It is one of the very best eyepieces money can buy.
I agree with the others in getting a good diagonal, the overall quality of the optical system is only as good as its weakest link, expensive eyepieces coupled with poor diagonals or barlows give poor quality views.
As has been mentioned, the WO dielectric diagonal is superb but expensive, the standard WO diagonal is very good and a bit cheaper. You can order these from:-
www.frontieroptics.com
Daniel Beringer runs Frontier Optics and is an excellent person to deal with. As in Ice in Space member he will do you a good deal.
CS-John B