I have an Asus A7V with an Athlon 1.2 and a Geforce 2 Ti and an Geforce 2 MX.
I use Windows 2000 and everything works just fine.
I think you should go for it and I think it will work fine, but I reckon it depends on your OS. Windows 2000 fully supports multiple monitors.
Nowthen, when I have run games they use only the primary monitor, but so what, your system should work how you want. By the way, you can make either card your primary (in W2K).
I have never used the TV out.
I have also had a Radeon 64mb DDR with TV in/out and a Radeon 32mb PCI and again everything worked fine for me and I have no reason to think the TV capabilties would not also.
I recommend a Radeon PCI card or their All-in-wonder Radeon deal.