Sharepoint 2007 gives better control and more types of fields. It is still dissapointing to see that some things are missing - when we are talking about people details the need for master-detail lists usualy comes up (if the person is from this department, he can only be from one of these teams).
Even so, user profiles do offer more customizability.
One of the exciting new things is the ability to add choice fields to the profile. These choice fields can let users pick information to describe themselves from a list of choices.
The field can be either Closed (The user must select from a predefined list of values only) or Open (the user can either select from a predefined list or enter his own text) and can be Multivalued (the user can select several values).
An example to such a list is the "Skills" list. You can populate the list of skills in your organization, and then every user can select the skills that he has from the list. Then, users in the portal can search for people with specific skills!
Another field type is the person field (like in the lists) - allowing the user to select from the list of users.
I am still researching on how to expose fields to the advanced search. Currently the advanced people search shows only certain fields, but I know everyone wants to search on different fields. The only option I found that is related to this is to select if the field is indexed or not, but that doesnt add the field to the search interface. If anyone knows how to do that - let me know!