Another shooter that we have enjoyed recently. Halo is a demanding game that really stresses even high end systems. We run a set of tests with both the Pixel Shader 2 and the Pixel Shader 1.4 pipelines. The 9800 XT leads in both resolutions and with both rendering pipelines. It looks like ATi has improved their Pixel Shader 1.4 efficiency after the 3.9 series of drivers as the 9700 Pro passes the 9800 Pro by a small margin.
UT2k3
Our final FPS is UT2k3. Results here are bit more varied. The 5950 and the 9800 Pro are neck and neck and flip flop back and forth. Again the 9800 XT cleans up. The numbers for all the cards are very good though and is playable at all resolutions with AA/AF on so if UT2k3 is your bag then pretty much any of these cards would suffice.