It's been a while since I refreshed my catalogs and I've got a huge amount of updates to apply. Far as I've been able to tell, the 770 only allows me to install updates one at a time...it is slow and painful. Anyone have a work-around that will permit installing multiple updates at the same time (or at least without me having to click on each and installing individually)?

What he said

Though I don't know why - I've heard people say that apt-get upgrade is naughty

Thanks very much! Worked great!

It may be naughty, but I do those plus apt-get dist-upgrade quite regularly, and it hasn't done me any harm that I know of.

The last time I did it, I had to reflash. Maybe I had "wrong" repositories that claimed to have updated system libraries (in fact I can see them as "upgradeable" right now), I don't know, but I prefer not to do it.

Then you were extremely lucky :-) Maybe latest Bora is OK now but there were problems with this many times before with maemo 2.x and 1.x repositories and there may be problems in future again. Application manager upgrades just user packages. 'apt-get upgrade' gets also libraries and other system stuff which can break things and did that many times to many people before. Maemo repositories are/were meant mainly for scratchbox environment so there is no guarantee everything will work on the device. Also some upgrades may lead to stopping/restarting of critical services which may reboot tablet in the middle of upgrade and cause reboot loop.

Here is one example that will force a reflash of the N800 with the latest OS installed.
The repository http://repository.maemo.org/pool/bora/free/binary/ has the libgtk2.0-0_2.6.10-2.osso30_armel.deb package that contains a broken gtk-x11 lib. So if your sources.list references the above repository your next reboot after your procedure will hang at ~90% (the splash screen with the Nokia hands will not show up) and cycle rebooting.
There are people here on the forum who claim this is expected behaviour.
http://www.internettablettalk.com/forums/showthread.php?t=8992

Weird, i did a apt-get upgrade recently and have that package and rebooted many times since without any problems... would the problem be in a conflicting install somewhere else?

Well, I'm thinking that maybe the apt-get wasn't such a hot idea...my 770 is in infinite reboot now. Now that I've reflashed, I'll not be using that feature again...guess it is back to downloading packages one at a time....sigh

I think apt-get upgrade could be particularly devestating if combined with red-pill mode.

I don't know why the NIT is set up like this.. if I do a test-upgrade (apt-get upgrade -s, which doesn't install anything) I see a lot of upgrades that certainly aren't visible inside application manager. This way of doing it isn't inherent in the Debian package management system, so I don't know why it's like this in the NIT.