In case anyone else runs into this, it did turn out to be an issue with OS X 10.4 which isn't present in 10.3.  Upgrading to Samba 3.0.20a (released yesterday!) fixed the issue.  I can now connect to the Debian server from any of the Macs with no trouble.

alex

http://www.macwindows.com/tiger.html#SMB1
The suggestion to clear the Keychain did nothing, but other notes on this page got me on to the idea of giving the latest Samba a whirl.

On Oct 1, 2005, at 3:48 PM, Alex Dean wrote:

I still have a problem.  I have two Macs on this network (OS X 10.4).  Clicking 'Network' in the Finder shows the server.  Clicking 'Connect', which usually shows the list of available shares and mounts the one selected, crashes the Finder every single time.  I think this must be something wrong with the Finder, since I'm now getting the same errors when trying to connect to another Samba server which I used to use with no issues at all.  (I recently upgraded from 10.3 to 10.4, so I'm now thinking that's the issue.)