radeon x2300xt will coming up this quarter. it may be a good choise for you if you have extra money.
it has twice power of geforce 8800 gtx. not to mention radeon x2600xtx pro.....
there's the source:
http://en.wikipedia.org/wiki/Radeon_R600
For one... The card isn't out yet, thus there is no hard evidence on the product,
So there is no telling what kind of performance we could expect, And Nvidia is planning on releasing another High-end Series 8 Geforce during cebit. (They always like to try and rain in on ATI's Parade...).
Still, You could be right, But until there are some benchmarks to prove the performance of both cards, I wouldn't start saying "its twice as powerful as the Geforce 8800GTX". Because you don't know if thats true.
4-6 months is a long time in the graphics card industry he may find that the card he buys now will suffice for a few years and not bother, But as it seems the Geforce 7300GT and 7600GS are the best recommendations at this point, As like they say always get the best you can afford/need at the time, as there is always something better around the corner. (Otherwise you may as well wait till your in the grave).