Linux restart after update... LOL
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In Linux, that means the kernel and possibly few other core packages, and if that's unacceptable for any reason, there's the magic of http://www.ksplice.com/ to help you out.
As an example, I have just updated the (intel) video driver in my desktop Ubuntu 10.10, and got no prompt to reinstall (arguably, it might be good for the system to ask me to relogin in order to start using the updated drivers - but it didn't). So in this regard, I haven't seen Ubuntu behaving worse than any other Linux distributions (and, I suppose, other normal operating systems), and behaves quite reasonably.
IIRC, you can't do that with Windows or OSX without some serious convolutions (rebooting often being easier)
A major difference, and really a big fault on Windows, is constant nagging to reboot, with window that pops up every 10 minutes or so. Ubuntu has really good visual cue (power off applet turns to red, see upper right corner) but allows the user to make that decision to restart when convenient.
And Ubuntu on servers is starting to become more attractive than Debian. I set up a Ubuntu media encoder under a Debian/lxc controller and it's remarkable how straightforward it was to assemble (with custom ffmpeg stuff)
Still I use it daily
Also, the machine is running Windows. Who wants long uptimes under that?