The SiS 680 chipsets will be targeted at the entry-level market. Here's an overview:
SiS 680SCE: Mirage 4 graphics, 1333MHz FSB support, DDR2 1066/800MHz memory, HDMI/HDCP
SiS 680SCP: Mirage 4 graphics, 1333MHz FSB support, DDR2 1066/800MHz memory
SiS 680SDC: won't have built-in graphics
SiS 680SCH: Mirage 4 graphics, 1066MHz FSB support, DDR2 1066/800MHz memory, HDMI/HDCP
SiS 680SCL: Mirage 4 graphics, 1066MHz FSB support, DDR2 800MHz memory