Navigating Sharepoint site structure from Office 2003

After using Sharepoint for our internal intranet for quite a while, one major problem has become apparent:

How to easily open and save items to the different document libraries located on WSS sites in the portal.

Customers are also pointing this out as a major disadvantage compared to the old-school file server. Users are accustomed to navigating directory structures and we need to find a similar solution when navigating the site structure.

Personally I've used the "My Network Places" pane in the Office save/open dialogs, but now I've got a billion links to "Shared Documents on portalserver" which is useless. Navigating to the portal root gets you no further than to document libraries located in a portal area (although you get a nice browsing experience through the areas). There should be some way of navigating the site tree from the portal root, via top-level websites and through the site directory right down to the document library you want.

If this can't be done users have to memorize and/or maintain an ever growing collection of links.