Firefox: part II (extensions)

extensions that you MUST have:
Adblock Plus
CustomizeGoogle
Firefox Showcase
Flashgot
Google Toolbar
Google Preview
MR Tech Local Install
New Tab Button on Tab Bar
New Tab Home Page
NoScript (a must have for security)
PDF download
QuickZoom
ShowIp (a must have too)

I'm not gonna go through a detailed description of each one. Just search for ad-ons directly from the Firefox interface or visit that page.