I am not a big fan of Vista User Account Control (UAC). It causes me issues and I'm a techie. For non-techies, this thing is just a nightmare. I grew tired of dealing with it, so I just disabled it. Then I tried to map to a network printer and received the error message "Windows cannot connect to the printer. The specified print monitor is unknown."
Weird. I installed the latest drivers on the print server and specifically installed Vista drivers but that didn't help. Then I googled and found Trevin Chow's blog post explaining that the problem was UAC was disabled. Believe it or not, the fix is to 're-enable UAC', add the printer, and then disable UAC (if you want to...which of course I do).
If you don't remember, to re-enable UAC you have couple of easy options. Just go to Control Panel, User Accounts, click User Accounts again, and then select "Turn UAC on of off". The other option is MSCONFIG and then the Tools tab, select Enable UAC and then click Launch. Either way, it requires a reboot after each change so for me that means two reboots just to install a printer!