If you feel the crunch upgrade video in March / April. (ie: now, or wait 12 months).
This will have little impact until March / April 2007. (next year)
If the video cards released in October 2006, this year, are going to be DX10 parts, they'll look poor in comparison to the '2nd revision' by April 2007 anyway.
It happens all the time, Either upgrade video every March / April, or every October... or every 2nd year depending on what you got last time.
The trick is selling your old video card while it is still worth something, and putting that cash into your next video card.