What you have mentioned in your post is still relevant today. However the proprietary "fglrx" driver for ati has caught up very much with the proprietary nvidia. So much so that i barely notice a difference between catalyst on windows and fglrx on linux. One area where ATI still lacks is HD video playback where there is no equivalent of nvidia's VDPAU. However with ATI opening up, expect much more work on the XvBA. So what i will recommend is that unless you watch a lot of HD movies. Go for Radeon. I have a 4650 and i am very pleased with its performance.
Unfortunately things are not that rosy on the opensource front. The noveau, radeon and Gallium3d drivers are all fine if all you want to do is compiz and maybe a few indie games. But all the open source solutions ( be it mesa, gallium or anything else) are still miles behind their proprietary counterparts. Right now the best performing Open Driver is the Gallium3D driver for the R600 ATI Chip ( Radeon hd 3xxx series), but its still not mature enough. So unless you have very modest requirements, you will have to go for the prorietary ones.
modprobe program to add and remove modules from the Linux Kernel. You can find more details using command man modprobe.
ifconfig eth0 up - It is same as enable a Ethernet device in windows.
dhclient eth0 is to get dynamic ip from your router.
ping intel.com to confirm that you can connect to intel.com i.e. Internet.
Now to do a modprobe automatically, edit rc.local file. rc.local file is special file that runs when you logon.
So run this command,
gksu gedit /etc/rc.local
at the end of this file before the line exit 0 enter a line like this
modprobe e1000e
exit 0
What the thing is kernel update and blah blah..
Kernel is the core of any operating system. So if the core changes all drivers must be compatible with it. Ubuntu provides update of kernels for stability and security. The kernel version is mentioned in grub menu like this text 3.2.0-25-generic . As you are building the driver yourself so any with any change in kernel you have to recompile the driver to make it compatible and include in this new kernel.basically you have to do the steps you did before modprobe. :)
Let me know if you need more clarification.
Anyway, did you check Additional drivers (press Win and type it), Ubuntu community might provide the drivers. In that case you don't need to do anything. It will be updated and maintained automatically.
Best Answer
Unity (12.04)
Ensure that you are connected to the internet, if you are installing wireless drivers then usually you need to be plugged in via an ethernet cable. Click on the Ubuntu logo in the launcher and type drivers and click on the icon that appears.
If you have hardware for which there are supporting drivers to download, they'll show up in this window and allow you to install them. If nothing shows up in this window then you probably don't need drivers installed for your hardware as they come bundled with Ubuntu.