User is on Outlook 2k3, latest service packs, updates, etc. Mailbox lives
on Exchange 2007 (SP1). Everytime the user starts Outlook they're prompted
to logon. I've disabled the logon prompt at startup option (and enabled it
and then disabled it again), but it's still happening.

I've tried it with cached mode on and cached mode off.
I've tried it with offline mode enabled and disabled.
I've tried deleting his profile and recreating it.
I've tried switching to an RPC/HTTPS connection.
Finally, i completely uninstalled Outlook 2k3 and installed Outlook 2k7.

Nothing worked. If i setup this users profile on another workstation, it
works fine. I thought the wireless connection might be screwing things up,
so i disabled it and only used the wired the lan connection. No luck.

The connection is set to automatically detect.