Agreed - plus you could go sli later (buy a 2nd hand one on the cheap) and not have to worry about changin your mobo.
Volt modded the GTX is better, but the X1800Xt is quicker out the box - but there is not much in them performance wise - the GTX is quieter and is a single slot cooling solution (can upgrade to artic colling silencer for better temps if required) the X1800 runs hotter and is noisey at full fan speed.
I'd go on price versus performance and on that basis alone the 256MB GTX wins for me.
Mav