Intranet and Internet Site on One Server

How good or bad to place both the Intranet and Internet Site on ONE NT box? Security issue is one of my concerns. Following is the environments:
1. Internet server and Intranet server use different MIC, then use different ID addresses
2. Furthermore, (since different NIC is used)the firewall can put the intranet in trusted network, and Internet on DMZ.
3. The contents of both sites are completely separated. One site will not access the other site’s contents.
4. Some of the COM components used by ASP will be shared across the sites.