[Samsung Galaxy Nexus] TECK:
I'm posting this guide because my Galaxy Nexus I9250 I purchased from Google Play would not to recognize in any way, shape or form the official Google drivers provided into Android SDK. Obviously, if you installed any Samsung drivers, you will have to uninstall them. Personally, I always connect the device to my PC and let Windows Update find the best driver. In this way, the basic Windows interface is handled by Microsoft drivers:

Google SDK 64bits Setup

This is a quick howto for those who actually want to setup their SDK properly in Windows 7 64bits. I saw a lot of craziness on the Internet so I wanted to share how I set a proper 64bits development environment.

Android SDK: http://developer.android.com/sdk/ (installer_r21-windows.exe)

Java JDK: http://www.oracle.com/technetwork/java/javase/downloads/ (jdk-7u5-windows-x64.exe)

Eclipse Classic: http://www.eclipse.org/downloads/ (eclipse-SDK-4.2-win32-x86_64.zip)

First, download the 64bits software versions, not 32bits. Android SDK is the only 32bits package but it will work fine with 64bits development tools, if you know what you are doing. Obviously, if you are on a 32bits OS download the 32bits software versions. We are discussing a 64bits setup, so let's move on.

Install Java JDK and only if you run a 64bits OS, set a JAVA_HOME variable with value "%ProgramFiles%\Java\jdk1.7.0_05" into Environment Variables (adjust the value with whatever version you downloaded):

Reboot your PC to enable all the settings done above.

Next, install Android SDK. You only need to download Android SDK Tools, Android SDK Platform-tools and Google USB Driver, if you just want to play with the phone. If you plan to develop apps, install also the API of your choice and Eclipse Classic (yes, that is the recommended version by Google devs).

To make available everywhere your platform tools (adb, fastboot, etc.), add your platform-tools directory to Path:

Myself, I installed the SDK in "C:\Program Files (x86)\Android\sdk" directory, so my path looks like:

%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;%ProgramFiles(x86)%\Android\sdk\platform-tools

Technically, you need to add the ";%ProgramFiles(x86)%\Android\sdk\platform-tools" location at the end of your current path.

Reboot your PC to enable all the settings done above.

Now, on with the fun part. There are 2 drivers needed for Google Nexus, the Composite ADB and Bootloader (Android 1.0).

Android Composite ADB Interface Driver

First, enable USB Debugging in your phone:

Plug your USB cable, you will notice in Device Manager the failed driver notice:

Right-click on it and select "Update Driver Software...", then "Browse my computer for driver software". Don't bother browsing to your ADB USB driver location, it will not install the proper driver. Instead, click on "Let me pick from a list of device drivers on my computer" button:

Make sure "Show All Devices" is selected and click on Next button:

With the list of devices displayed, click on Have Disk button:

Browse to your Google Driver location, mines is set in "C:\Program Files (x86)\Android\sdk\extras\google\usb_driver":

Pick the "Android Composite ADB Interface" driver and click on Next button:

You will be asked to accept the driver installation, do it and be done with this part of drivers setup:

Android Bootloader Interface Driver

Make sure USB Debugging is still enabled in your phone. With the USB cable connected, manually boot into Bootloader mode by powering down your phone and restarting it with all 3 buttons pressed (Volume Up + Volume Down + Power). You will notice in Device Manager the new unrecognized Android 1.0 device. Follow the same steps explained above and when you reach the driver selection, choose "Android Bootloader Interface":

To test the setup, run few basic commands:

adb devices
adb reboot bootloader
fastboot reboot

You are done, enjoy the official USB drivers from Google.