You can reconfigure the position of the driver letter in Explorer in Vista and Windows 7.
Before (XP and earlier), the driver letter would always be shown as first. Since Vista, this behaviour has been changed, but can luckily be controlled by a registry setting.
To change the setting, fire up regedit, and edit/create a DWORD value, called ShowDriveLettersFirst in the root of the key HKEY_LOCAL_MACHINE\Microsoft\Windows\CurrentVersion\Explorer. This controls how drive letters are displayed in Explorer. The values are:
When the registry key is set, restart your computer for the changes to take effect.