662 is coupled with one of two different southbridges, either the 966 or 966L. They will both feature PCI Express 1x connectors. SiS662 also has a single PCI Express 16x connector, so while you won't be getting SLI support you'll definitely have room for a beefier graphics card.
While the 662 isn't a showstopper, SiS has shown great improvement with their chipsets over the past few years and have been doing good at offering less expensive or better fitting alternatives to other chipsets. Let's hope that holds true for SiS's newest lineup.