3 words: "never say never"
Any developer/designer worth his salt should know when and where to use popups and how to minimise their use. Unfortunately for the zealots, there are actually usable situations where popups are more usable than alternative solutions (e.g. lightboxes, floating divs). Sure 99.9% of the time you aren't going to use a popup.. The minute you start using absolutes to convince yourself that your the man when it comes to usability, you've shot yourself in the foot. Work with your users, don't dictate to them. (By the way, when I say 'you' I don't mean Shermozle, I mean all of us).
IMO, popups work well as dialogs and are more user friendly than lightboxes as they are closer to the functionality of the OS. IEs modal dialogs work well. Ajax popups that float around or flicker on and off or get stuck because a mouse event doesn't fire properly is not really that usable.
Unfortunately, browser makers have lost trust in developers to know when and where to use them and we've now lost control to popup windows with full control - the bastards have ruined it for the rest of us and we have to deal with popup blockers and firefoxes open in a new tab option.. oh well. Personally I'd like to say 'open in new tab', 'open in new window', 'open as lightbox' ... that allows me to make an educated professional decision.