A Minimal Gnome Installation

To achieve this I opted for a network install from a minimal CD : http://www.debian.org/CD/netinst/. The network install assumes that you have a connection to the Internet. You can choose between a netinst CD image or a smaller businesscard CD image. The netinst image contains the installer and the base system. The smaller business card image does not contain the base system, but only the installer: even the base packages need to be downloaded from the net.
I grabbed the debian-6.0.1a-amd64-businesscard.iso which is only 49.0MB in size. Just to mention here one of the cool features of the businesscard installer - not found on the netinst.iso and other media - is the option to select for installation any one of Debian's 3 different release versions. See picture below....( Advanced options > Expert install )

Debian CD and DVD images can now be written directly to a USB stick, which is a very easy way to make a bootable USB stick. ( see : http://blog.einval.com/2011/01/07#isohybrid_CDs ).
Plug the USB stick into your host machine and leave the stick unmounted. Run the dmesg command and note the USB device ID (In my case the last line was : [ 6101.712220] sd 8:0:0:0: [sde] Attached SCSI removable disk )
Make sure to record the correct USB device ID. The following procedure wipes out all data on the USB stick :
# cat debian-6.0.1a-amd64-businesscard.iso > /dev/sdX
# sync
( in my case X = e ).
Make sure your computer starts from usb ( check BIOS ).
First screen will be :

Just press Enter....

A number of screens later you'll reach the next one :

Only install Standard System Utilities.

When it's all done, reboot and you'll be greeted by the next screen :

After boot process login as user and enter your user's password....

Become root with the command su and enter root's password....

To prevent apt from suggesting/installing recommended packages we'll add two lines to /etc/apt/apt.conf :
nano /etc/apt/apt.conf
Add these lines :
APT::Install-Recommends "false";
APT::Install-Suggests "false";

To install a minimal Gnome :
apt-get install gnome-session gnome-themes gnome-terminal xserver-xorg-core gdm3 gnome-control-center alsa-utils

Start your first session :
/etc/init.d/gdm3 start

After your login start a terminal and run alsamixer :

The current version of alsa installs with all channels muted by default. You will need to unmute the channels manually. The label MM below a channel indicates that the channel is muted, and 00 indicates that it is open.
Unmute the Master and PCM channels by scrolling to them with cursor left/right and pressing M . Use the ↑ key to increase the volume and obtain a value of zero dB gain. The gain may be found in the upper left next to the Item: field.
Test sound with the next command :
aplay /usr/share/sounds/alsa/Front_Center.wav

You're done so far....time to add packages you want and need....