Power User Marketing and Development Tools For The Savvy Affiliate

Text Editors

e-TextEditor: My preferred editor. Supports most Textmate bundles (Including the awesome Zen Coding bundle), which makes hand-coding HTML a lot less tedious.
Zen coding plugins: Set of plugins for HTML and CSS hi-speed coding. Makes your life easier.
EmEditor: Another full-featured and mature editor. Particularly good for dealing with Asian languages, as the developers are Japanese. Has a great TSV/CSV mode. Recent versions have added a lot of great features. Strong snippets implementation. Has every feature in the book, without a cluttered interface.
Textlab Text-extender: Adds extra methods of formatting and transforming text data with any app (browser/text editor/etc).
R10Clean Data Manipulation and Cleaning Tool: Powerful cross platform utility which will help you to clean, manipulate, de-duplicate or fix large amounts of data very easily. You can even import the data from a CSV file, TAB Delimited or Text file, then modify the data and then save it back in many other formats like native Excel(XLS), TAB Delimited and Comma Separated. You can even save the modified file with your own Custom Delimiters. R10Clean supports the following Actions: ,Remove, Replace, Find, Insert, Format. Well worth a look.

Also See

Search / Replace tools

Even though most of us are moving sites to CMS's or similar systems, rather than doing everything by hand, there are still sometimes the occasion where you need to replace some obscure string in a hundreds-thousands of files. (eg needing to change hard-coded links across an entire network of sites). Anyone doing that sort of thing manually is bonkers.

Text Workbench

Text Workbench is a multi-purpose search and replace tool with full Unicode and UTF-8 support. I only came across this app recently, so I haven't actually had a real issue to test it with yet.Can also be run from the command line, useful if you're scheduling things with it.Some of the useful functions are;

Finds and replaces text in file names (renames files).
Insert random identifier;
Case transformation operators;
convert a symbol or a text portion to HTML entities;
Insert contents of a whole specified file;

HandyFile Find And Replace: Office Edition

Same sort of thing, but for office docs (Word, Excel, Powerpoint). Very decent for the price.

PowerGREP – Search and replace tool

Very powerful Search/Replace app. Has been around for ages and is well supported. Does everything including text and binary files, compressed archives, MS Word documents, Excel spreadsheets, PDF files, OpenOffice files, etc. If you're comfortable with (regular expressions) this is the one to go for.

Windows

Directory Opus: Explorer replacement with every feature you'd possibly want. After using this for years I can't imagine going back to plain old explorer.
Everything desktop search (freeware): Lightning fast windows desktop search. Indexed 3tb+ on my machines in 20 seconds or so.
AIMP2 Audio player (freeware): Because working in silence sux as much as recent versions of winamp and WMP. This sounds great, plays everything, supports multiple playlists etc etc.

Automation / Macro tools

Automise: Automate complex repetitive tasks with ease. Use any of Automise's built-in actions to automate a single task or combine actions in a workflow to automate an entire IT process. Once a project is complete you can run it with a single click, keystroke or automatically on a schedule.
daVinci Script: Another great piece of automation software for Windows platforms.; Swiss File Knife; Open source automation software.

Version Control Systems

BitBucket (Mercurial): Bitbucket is a code hosting site, for the popular Mercurial version control system.
GitHub (Git): Git is an extremely fast, efficient, distributed version control system. Github offers free and pro accounts to host your code on.
TortoiseHG Windows mercurial client: TortoiseHg is a Windows shell extension and a series of applications for the Mercurial distributed revision control system.
MysGIT: Git client for windows.

Online Services / Web Apps

Quick Tools for Google Apps: Quick Tools for Google Apps runs in the Windows system tray and notifies you of new email and calendar events. You can quickly perform tasks such as adding appointments to your calendar or uploading files and folders to Google Docs.