3 monitors (2 DVI, 1 CRT), 2 video cards. Where to plug in CRT monitor?

[JEDI]

mobo= AMD690G chipset

onboard = ATI RADEON X1250 (DVI and Dsub)
PCI-E = GeForce 6200LE (DVI and dsub)

3 monitors:
2 20" LCD (DVI)
1 17" CRT (Dsub)

obviously, will plug the 20" LCDs into each DVI port.

Which video card to plug the CRT into? WHY?

THX!