How long do you intend to use the machine for? There will be little 64 bit software out for a year or two more so I would not use that as a purchasing criterion.
I don't know much about graphics cards but would think that what you have will be more than enough.
PCI express is more up to date so there is a lot of sense in going for it.
So, no real answer but I would go for the intel option as it supports PCI express; others will likely go the amd route for the 64 bit option.
Either way, you have a good basis here for what you want. Add a decent monitor though if you are doing a lot of graphics work.