The Geforce 420M is better than Intel graphics. Don't let the memory amounts fool you. For normal office tasks, either will be sufficient. If your business/marketing purposes include anything graphic intensive, the Geforce 420M would be a better choice. My guess would be that you don't need the advanced graphics of the Nvidia card.
The Geforce is way better than the intel graphics card. If you want this computer to last some time the Geforce will be better. Either way the will both suite your needs fine. Me, Personaly I would go with the Geforce.