I agree , dont worry and be happt , the chances are you will buy a DX10 card when you know you will need it, and that is not going to happen at least another year, probably two the way things are looking.
The card you have is not very far from the 360 chip , so i wouldnt worry.
Let me put it this way. I have used the same 9500pro since it first hit the shelves at the BB that I worked at. Until recently the card has been great and the only reason that I am just now upgrading is because everything in my system is 5+yrs old and needs to be upgraded. I could probably use the 9500pro in the ASrock board that I will be receiving today, but I decided to upgrade to a 7600GS while I was at upgrading the rest of the computer. You now have one of the top of the line cards. Believe you will not NEED to upgrade for quite some time, wanting to is another story.