With the new ATI release of the 1900xt 256mb, which video card would you buy?? Would you get an 1900xt 512mb for $289 (that is after a 100 dollar MIR), an 1900xt 256mb for around $280 (MSRP), or a 7900gt for $289 (that is the Evga one that is factory overclocked to 580mhz core and 1580mhz memory). It will be going with a 6400 conroe system.