I've posted a few suggested improvements for the Leads inbox - here's another one.
If the suggested flow for the leads inbox is to use this as a "unqualified/suspects" box (which I agree with), I think you may want to consider adding a "permission" that allows admins to indicate which user set can create contacts and organizations.
If the lead box eventually will work as suggested in another topic, the only way to create contacts/organizations is through conversions of the lead qualification process (this is how I had it work in SFDC and Zoho CRM). In that case, I would want to make sure I can disallow users from creating contacts and organizations directly. If not, you still end up with a mix/match of unqualified records.
Since others may have a different workflows, I'd add this as an option so people can choose how they implement the flow of suspects - prospects - customers in their sales process.
@Mike van der Valk - just my 2 cents.