Way to answer the guy's question.
I'd say AMD. I used an older AMD on FS98, and it worked great. no lag no nothing no matter what the res. However, this game seems to be mostly determined by the video card, not the CPU. So yes, the only difference you will really see is between video cards. And the Radeon 9700 Pro would be your best bet for the best graphics.
XP 2500+ Barton
2x512MB Corsair PC3200
ATI 9700 Pro
2x80GB 7200RPM Maxtor