RM, you look like you have similar computer buying habits as I do (at least looking at your sig, I am also running a 5900 card, which means you haven't upgraded in about three or more years). You make the technology leap when you feel it is justified, but in between those steps you try to build a system with at least some upgrade room if possible. I am waiting until the mid-range DX 10 cards hit the streets (or at least until there are several price points available for DX 10), and I would guess at least some of those will be in the spring, hopefully not much longer than that.
So if you are like me, and will have a video card in your system for at least two years before making an upgrade I think it is reasonable to wait until the graphics market gets a decent DX10 card out the door at the price point that fits your strategy and what your wallet can handle. The way it looks like DX10 parts are being built seems to indicate to me that even mid-range parts will have good performance in almost all DX9 titles, certainly a giant leap over what you are currently getting, at least IMHO.
Good luck.