^ exactly. At this point, if everythings going fine with your gaming, Id hold off, if 6 months is reasonable to you, and be looking for the next gen, where DX11 with all its goodies will come into play.
Ive a feeling, DX11 cards will transition to games much much easier than past DX' releases, as its just a superset of DX10. Or, to put it more simply, the first DX11 cards should provide a decent DX11 experience, unlike in the past, where so called first gen DX cards couldnt really handle the new DX they were designed for, and it was the second such releases that really shined. Just look at how well the G80 series handled DX10, which is (G80) almost as old as your 1900, tho a much more robust product, but only midrange currently in todays standards