Upgrade nagging: Good or bad?

Most of the time I hate when a program nags me to upgrade it.  Everywhere I possibly can I disable automatic updates, but some things still say "hey! hey! there's an update! hey! hey! get the update! hey! hey! why haven't you gotten the update yet?" and so forth.  I'm thinking mainly Firefox here, which pops up at least two nag windows a day if there's a new version out.  Which oddly enough makes this all the more ironic.

Thunderbird on the other hand, doesn't seem to care one way or another.  Most of the time it will pop up a box saying there's a new version, but it's not insistent about it.  I didn't even know Thunderbird 3 had been released until just recently when I noticed a subtle change to the page I always see in the email pane.

I semi-recently set Steam to not always fucking update my games (really only Portal, the demo of Serious Sam HD never has any updates), but it seems to revert the option whenever it feels like it.

I can't even update Thunderbird yet, because one of the extensions I use (Contacts Sidebar, and why the hell isn't this extension's functionality standard?) isn't compatible with 3.* yet.  Apparently there's a prerelease version that is, but I think I can wait until it's actually released on addons.mozilla.org.

I only use two extensions in Thunderbird anyway, and both to do things that I feel should have been standard features.  Contacts Sidebar makes dealing with contacts a lot easier, simply double click one to start an email, etc.  It's basically adding the built-in functionality of the Contacts pane in Outlook Express.

I have Stylish installed, with one style that I wrote myself.  Ever notice how when you expand the header view, it takes up the entire email pane and you can't read the message?  Yeah, this style forces it to have a maximum height and provides a scroll bar.