Wow - that's a pretty open ended question.
Depends if it's an intranet portal for SharePoint sites or whether it serves as an organisation wide intranet.
In my experience a useful organisation intranet homepage is one that essentially acts as a launchpad for easy access to sites/services that a user either needs/or is looking for. Having search capability right there is a must.
Some organisations I've worked for want all the bells and whistles on that first page, the CEO's blog, a corporate/organasational newsfeed, company wide announcements for example, access to the internal directory.
If it's purely a SharePoint intranet it usually is quite generic, with the pointers to all the ket top level sites available.
good luck!
Technical Consultant
Parative Consulting Services