Networking was easy to bring up temporarily: I had to bring up the interface by hand and networkmanager would no more see loss of link and bring down eth0, which in turn triggered one of my scripts to bring up wireless on eth1.

The upgrade to Xorg 1.5.3 was supposed to be a good thing, but it made X crash every 10 minutes or so with fglrx (which was nicely upgraded for me), or with the radeonhd driver. I first had to upgrade my kernel to 2.6.27.7 (from 2.6.24) to stop the crashes, and after a fair amount of work, got the radeon and radeonhd drivers working with my mobility firegl V5200 (3d almost works, it just crashes with radeonhd and is very slow with radeon, but when I have time, I'll do some svn pull to get even later drivers and it should work I'm told).
At least the good news is that I'm now running an OSS radeon driver, no more fglrx binary blob. I also get 3D and for the very first time: AIGLX and compositing in enlightenment.

Networkmanager might be supposed to be cool, but totally fucks up your life if you're not using it exactly the way it was intended. I had auto plugging working, that stopped after an upgrade. I had auto switching from wired to wireless (through dhcp scripts) and that stopped too (after networkmanager took over the function of ifplugd), and that stopped working too. After that, I even got networkmanager to just SEGV in protest.

Then, I tried to make networkmanager work, but I soon found out that it's been riddled with bugs and not been playing nice with the rest of the system if you have non standard configs or need to admin some interfaces by hand. Sure, it has an exclude mode, where it will now not even bring the interface down on loss of link (it used to), forcing me to go back to ifplugd or the newer wicd.
The old network manager had null asserts that I reported and were never fixed.
The new one is even worse, it segvs if I manually bring up eth1:

NetworkManager: <info>  Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)
NetworkManager: <WARN>  nm_supplicant_interface_add_cb(): Unexpected supplicant error getting interface: wpa_supplicant couldn't grab this interface.
[1]+  Segmentation fault      NetworkManager --no-daemon

Then I tried starting clean by removing all my interfaces from =/etc/network/interfaces=, and networkmanager refused to manage my interface anyway. It looks like it's one of the many problems that people have been seeing.
I like the fix, which says:

As a workaround removed network-manager
sudo apt-get remove network-manager
And i started my network device with:
sudo ifup eth0
Hope this helps

And then, as I read the pretty light docs with no info on real troubleshooting, or WTF won't it even manage my eth0, I see gems like these:

you may want to restart the system-settings daemon using the command:
"sudo killall nm-system-settings" to apply those changes.

NetworkManager, you're not managing any of my networks anymore. It looks like wicd will do the job, and if not I'll just go back to ifplugd and custom scripts.

Ubuntu folks: you put out a good distro, but your love affair with gnome and utter shite like networkmanager is not making you look good.