Best-of-Breed Web Development Tools

This is a list of tools, modules and libraries that I consider to be 'best-of-breed' for web development. This is heavily geared toward the areas and platforms that I use regularly; esp. Mac OS X, CentOS, FreeBSD, PHP, Javascript/CSS/HTML and Postgres/MySQL.

Architecture/Planning

Omnigraffle is the go-to program for designers and UX people to do wireframes & sitemaps. There are a number of excellent stencils, such as the Konigi Wireframe Stencils
For technical/database planning, I like MySQLWorkbench. It's finally fairly stable, and can export MySQL code directly.

Web Development Tools

Text Editor: Coda (Mac OS X) is my current favorite. TextMate (Mac OS X) or BBEdit (Mac OS X) are also good.
WYSIWYG Editor: Adobe Dreamweaver
MySQL/PostgreSQL Admin: Navicat Lite - The latest version integrates MySQL and PostgreSQL management into one app. The Lite Version is free for non-commercial use. Also, PgAdmin is a free, powerful PostgreSQL administration tool. SequelPro is a new MySQL admin tool based off the excellent CocoaMySQL.
Firefox Add-Ons:
- FireBug - The DOM/Javascript Debugging Tool
- Web Developer Toolbar
- Live HTTP Headers
IE Add-Ons:
- Internet Explorer Developer Toolbar - Perhaps best called a poor imitation of FireBug, but still useful for debugging in IE
Safari Add-Ons:
- Web Inspector Tool: Not an add-on per se, but still a useful Firebug-like tool to enable.
Broken Link Checker: Integrity is a free, fast broken link checker.

PHP Modules

Mailing Class: PHPMailer
Documentation: PHPDoc
Template Engine: Either Smarty or Fry Template. Smarty is much more popular, and is much heavier (read: slower), but is more capable. Fry is new, object oriented, and lightweight.
Image Manipulation: PHPThumb

HTML/CSS/JavaScript

JavaScript Library - Lightweight: jQuery - For simple, easy DOM manipulation, you really can't beat jQuery. It's fast, lightweight, very easy to use, and has broad developer support. It doesn't do as much as YUI (see below), but what it does do it does better.
JavaScript Library - Full Featured: Yahoo! User Interface Library - This library, which is currently (Summer 08) under heavy development at Yahoo, handles a lot of the nitty-gritty DOM manipulation that you'd otherwise have to do yourself. It lets you easily create animations, put up popovers, deal with JSON objects, make AJAX requests and the like.
Analytics/Traffic Reporting: Google Analytics - Google Analytics is hands down the best free website analytics package out there.
Share System: ShareThis - great tool for sharing pages via email, with Digg, etc.
In-Page WYSIWYG Editor: FCKEditor is probably the best stand-alone WYSIWYG HTML editor. If you're using the rest of the YUI framework, YUI's Rich Text Editor bears looking at. You should consider using either in conjunction with HTML Purifier
Standalone Lightbox/Popover: I really like GreyBox and Lightbox
Video Player: FlowPlayer is the way to go. Both free and paid versions.
PNGFix: Drew Diller's PNG Fix is a good one. So is the jQuery PNGFix, although it is older.

JQuery Plugins

Lightbox: Thickbox - simple, flexible lightbox built on jQuery. Also good is FancyBox
The jQuery Tools Package is fantastic…Tabs, Tooltips, Overlay, Expose, Scrollable & FlashEmbed. It's stable, well documented and well supported by the community. Great, flexible APIs too.
Slider: Anything Slider is pretty good. Also check out the Coda Slider Effect
Accordian: Jquery's built-in accordian() function is pretty good.
Cookie: The standard cookie plugin is as decent as any.

Backend Tools

Database: MySQL is the usual standard for web development, but PostgreSQL is a very solid choice. Harder to learn, but much more powerful once you're there.
Caching Layer: memcached

Web Site Apps

Wiki: Dokuwiki - great, standards compliant, full featured wiki software
Shopping Cart: XCart - the best PHP shopping cart I've found, but it isn't great. Perhaps there are better options?
CMS: Drupal - top notch, flexible CMS software
Mailing Lists: oemPro - best PHP mailing list software I've found. N.B. I generally recommend outsourcing email to a service (and not using oemPro or any other software), as there are too many things to deal with when sending it yourself.
Message Board: PHPBB or VBulletin