I am a long time Opera browser user, when I first downloaded Opera, around ten years ago (there was no Firefox browser back then, its predecessor was called Netscape), it took me a few days to get used to it as I only knew Internet Explorer. I consider the three or four days it took me to learn Opera browser tricks and configuration one of the best investments I ever made.
As a long time user of I am probably biased towards the Opera browser, when you learn most tricks about a piece of software you will usually work quicker with it than something you do not know very well.
Opera is the internet browser I use and it is the best for my needs, it does not necessarily means it will also be good for you, maybe some Firefox addon that is really a must have for something you do will not be available in Opera, or something else that your browser has and Opera can not match.
I have used six other browsers, Internet Explorer, Firefox, Konqueror, Safari, OffByOne and K-Meleon. Besides Internet Explorer which usability goes beyond all common sense, I like all of the others.

Opera browser9.6 layout above
For those who use the Opera browser, here goes a list of security and privacy widgets that may come in handy to add:
Text Encryption widgets:
UniCrypt: A widget to encrypt/decrypt given string. Supported algorithms are: MD5, SHA1, SHA256, URI, base64, xxTEA, AES, Blowfish algorithms are supported
Text Encoder: Encode and Decode Morse code and Base 64.
€ncryptør: €ncryptør lets you encode your text so that only other people using €ncryptør (or yourself) can view its contents. Note:This is not secure encryption against the Mi5!
EnKoder: This is a text encoder/decoder based on the TEAencoder . It supports paraphrase/password encryption.
Password Hasher: Password hasher creates secure passwords by performing an HMAC SHA1 hash of a general parameter (Gmail, Yahoo!, etc) and a “master password” provided by the user.
NOTE: Be aware that these encryption widgets will not stop professional snopers like Mi5 or CiA from reading your text! But they will slow them down.

Opera widgets running on MAC OS
Disposable Email Address widgets:
Yopmail: Have a disposable email address for Internet registrations. All inboxes are available without registration and password.
Temporary Inbox: This widget uses the service of Temporaryinbox to create and check throw-away email addresses.
Computer Internet Protocol research widgets:
IP Calculator: This widget calculates network information from a given IP address and netmask, address are shown both in dot and bit representation.
GWhois: Get the whois information for a domain name.
IP Address: This widget shows your current public IP address, for users with dynamic IP addresses.
Web Node Info: The widget shows the Response headers of various Web nodes/resources. It also highlights redirects and response codes. It supports the HTTP and HTTPS URI schemes.
Binarization: Simple conversion text to Binary and Binary to text.
Internet Search Widget:
Google Hacks: Search the Internet using not well-known tricks to search for music, books, videos, lyrics, fonts, applications and torrents.

