I just figure that the higher FPS will carry me a longer way down the road. When programs suck the life out of the FPS down to the 30 minimum range I will be thankfull that it's a year later with one card than another.
I understand that thinking but it seems to be contrary to practice.
Often the one that had the higher FPS turned out to be the long term loser. The FX5900 often beat the R9800 is raw FPS, but the longevity of the card hit a wall when true DX9 titles hit. And while the X800 series was dominant in it's time, once games started moving to SM3.0 as a minimum then it got locked out of some titles.
There's no way to know which is which until a few years afterwards, and likely by then you'll own a different card anyways, it's rare people buy the current high end, and don't replace it within 2 years.
The only exception to the pattern may be the X1900, but even then I doubt there will be much more longevity for that series than the GF7, because both are extremely competant DX9 cards, and while the pixel shader power of the X1900 is slightly better, it's unlikely it'll ever have the kind of killer benefit that the R300 or NV40 had for longevity where there was a clear winner.
This round we won't start to know until the R600 launches and we can compare strengths and weaknesses, and even then we won't know until the first bunch of DX10 titles come out and we see how they are stressed in future titles. I suspect both will be very competant for at least 2 years, but of course wil be replaced by the ever better G90/R700/G100/etc. long before it matters for those who like to stay current anyways.