I would like to raise one counter-opinion to the video I just watched on combos. I find value-based combos useful.  I divide my d/bs into "Entities" and "Attributes".  Entities are Prime (People, Organizations, Projects etc), Action (Events, Notes, Tasks...) and Document Entities (Docs & Bundles....).

The power of the d/b is the linking of entities with many-to-many links where, of course, in the link table, I display the linked Entity with a query based combo box.  But, for attributes, I find a value-based combo, with limit to list and allow edits, to be very useful.  Examples are Document Type and Status, jurisdiction of a company - where companies such as US and Canada companies need to show both country and state/province.  By using a limit-to-list, allow edits value combo, every user can help build the list dynamically as the need arises without thinking unknown things in advance.

Yes, it needs a bit of management discipline but we have to have some confidence in our users ....

Of course, this only applies to a combo-box that is limited to a single form