Radeon 9800XT, hands down.
But if you must have THE BEST, and money is no object, wait a couple months. Ati & Nvidia's next gen cards will be released soon, nobody knows which will be the best of the two yet.
And expect to pay the better part of a grand to get one...
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<b>Radeon <font color=red>9500 PRO</b></font color=red> <i>(hardmodded 9500, o/c 322/322)</i>
<b>AthlonXP <font color=red>~2600+</b></font color=red> <i>(o/c 2400+ w/143Mhz fsb)</i>
<b>3dMark03: <font color=red>4,055</b></font color=red>