Remove or rename /etc/apt/preferences

Then...
# aptitude keep-all
# aptitude update
# aptitude dist-upgrade

thanks rickh, everything works great!

# aptitude install aptitude-doc-en
... or, "cs" "fi" "fr" or "ja" depending on your preferred documentation language.

That will install the Aptitude User's Manual on your hard drive where you can access it with your web browser, here:... file:///usr/share/doc/aptitude/html/en/index.html

If you're going to use Debian, it's critical that you understand the sources.list file and the package manager. Since I did some hand-holding here, which is not a habit of mine, let me advertise a couple Howtos I have written to help people understand Debian a little better.

How to Have a Pleasant Installation (for Debian Newbies)
Howto: Set up and Maintain a Mixed Testing/Unstable System

So after doing a 'aptitude update' and a 'aptitude dist-upgrade',
I'm left with no GDM, and no gnome, and I get an error when I try to install each
of them.
I am currently writing this in links

What's the error?

A wild guess... You might try...
# aptitude install xserver-xorg-core xserver-xorg xorg gdm gnome-core

Yeah I had to work out some dependencies and uninstall a few packages.
I finally got gnome-core, gdm and X11 installed, but gdm segfaults everytime I load it, and when I get into gnome, I can't click on anything, and my desktop keeps dissapearing...

IMNSHO the worst option when dist-upgrading from an older release to a newer one is using aptitude, especially with keep-all. If a package name has changed, aptitude will try to keep the old package installed, and your dependencies are borked.
Read what people running unstable think about aptitude, like here: http://sidux.com/PNphpBB2-viewtopic-t-5542.html
Aptitude is good for stable, perhaps even testing if you know what you're doing, but I wouldn't recommend using it on sid, or dist-upgrading between releases.

I think it's particularly important for Sid, and your evaluation of what it will do if a package name changes is complete hooey. Debian's official documentation recommends it as the preferred installer since Etch. Sidux is a good, if unnecessary, distro but they, of course, have a vested interest in scaring people away from Debian proper.

OTOH, to the OP, you've gone beyond my level of expertise and knowledge. Nothing like what you describe has ever happened to me. Just lucky, I guess.

Well, let's go a bit off topic then. If the OP asks, it stops.
What's important for Sid? Aptitude? Bollocks. Read the thread with links.
Installer? If you meant package manager, Debian recommends it for Etch and Lenny.
They aren't trying to scare people away from debian proper, just say use apt-get instead of aptitude.
And no, I don't use Sidux.
Just for fun, google: aptitude "stable to testing" site:.debian.org

@pietruszewski:
Try to find packages still from etch with "dpkg -l|grep package" et al. Do you still have old ones?
What would "apt-get update && apt-get dist-upgrade -s" say?

Oh wow, being a new linux user I have no problem just reinstalling testing - which is what I'm going to do. I find using Linux to be a 'fun learning experience' I guess.
makuyl or rickh, could you please explain to me the difference between using apt-get and aptitude? I used to run Debian on a 'dumb-terminal' without a WM, so I thought aptitude was the 'graphical' equivalent of apt-get, but I am so wrong apparently.

First return:
You have to remember that much of the 1000's of pages of Debian documentation was written before Aptitude existed. Since the terminal syntax will usually work with either program, common procedure for the writer's is to simply note at the end of a series of apt-get commands, that aptitude is now preferred.

The OP:
To be truthful, that's what I would recommend. A lot of people consider re-installing to be some kind of failure. I think it's kind of a rite of passage. Re-installing is one of the most educational things a Linux newbie can do. I'll bet I did it 10-12 times when I first started. By the time I really understood the installation process, I had no more problems with upgrades, etc.

Debian Testing Installer. I also recommend that you at least skim through the first link I left above.

. One would have thought you would know that debian devs recommend aptitude over apt. Skip the propaganda now and read a couple user problems and how they solved them from lists.debian on that google find. Enough OT from me for now.

I looked through the 2-3-4 year old list discussions that you recommended. It's an old argument. Although it became obvious to really knowledgeable people (the developers) early on that Aptitude was far superior to apt-get, regular users often had the typical reaction to "new things." The arguments continue to this very day on Debian specific forums, but the weight of evidence has gradually shifted to Aptitude. The best proof of that is that the apt-get developers themselves are working hard to get apt-get to behave like aptitude. The versions of apt-get in Lenny and Sid mimic aptitude's handling of "recommends" and "dependencies". If you don't like the default handling, it's easy to change.

I know the Debian etch installer like the back of my hand - after trying to get debian working on an Apple Macbook. Oh jeeze, that was a headache and a half.


I'd like a straight forward comparsion please, I can make up my own opinions after I've used either one to screw up my install.

This article has been widely circulated over the last year or so.
http://pthree.org/2007/08/12/aptitude-vs-apt-get/

apt-get and aptitude maintain their historical data in different files. As a result, if you mix the two, one will be lacking knowledge of applications installed by the other. Believe me, this does lead to problems. "aptitude keep-all" simply says, check out the entire system to see what has been installed by any means, and add it to aptitude's history file.