Plugins

 
Plugins are either small supplementary programs for the basic WordPress operation, or upgrades for its stock functions.  They're easy to install and easy to turn on and off.

While most plugins just need to be activated to work, there are a few that need a small tweak made to some system file first, so check for docs or try the home site if something's amiss.  And always glance over the 'Installation' page when downloading a plugin from the WordPress site.

Some plugins have settings on the 'Settings' page, and some need to be flipped on in their settings before they'll work.  It's a good habit to check the 'Settings' page whenever you install a new plugin.

Some plugins work in the background and aren't normally accessed.  Plugins that are actually run can be anywhere.  The 'Tools' area is the most popular spot, but you'll find them throughout.  Some of the 'global' ones place themselves in the Dashboard area, some of the theme-related plugins put themselves in the 'Appearance' area, plugin-related plugins might plop themselves in the 'Plugins' area, and some plugins will have the audacity to plunk themselves right on the tool bar.
 

Must-haves

CKEditor — the best of the second-party editors

WP-DBManager — backs up database, just in case

Exclude Pages — easy way to keep pages from displaying in the sidebar

Broken Link Checker — checks for broken links and lost pictures

Remember Me — keeps you permanently logged in

If you're allowing comments:

Better Comments Manager — more control over comments

Subscribe to Comments — notifies user when additional comments are left

Si Captcha — Used to prevent spamming

A whole bunch of comment-related plugins here

Forms:

Dagon Secure Form Mailer — simple contact form

CForms — excellent full-range contact form w/skins

System:

All In One SEO Pack — optimizes site for search engines

Category Order — allows you to sort categories in sidebar

Disable WP Update — turns off pesky WordPress 'update' feature

Favicon Rotator — Embeds favicon, rotates multiples

Google Analyticator — makes hooking up with Google Analytics easy

Last Modified Timestamp — sorts main list by last modified date

List Category Posts — automatically lists posts by category on page

MultiPages Widget — multiple page listings in the sidebar

My Link Order — allows you to sort links in sidebar (theme depending)

Page Links To — redirects page to web site

Search and Replace — does a global text search & replace

Search Everything —  much better search feature

Search Unleashed — another search replacement to try

Show Last Edited — displays last 10 edited posts

Simply Show IDs — Lists ID numbers of posts, pages & categories

Sitemap Generator — lists all posts & pages

TD Word Count — gives total word count of pages & site

TinyMCE Advanced — additional functions for the stock editor

WP-Optimize — compresses database

Multimedia:

Slideshow Gallery Pro — Decent slideshow program

FLV Embed — streaming FLV video player

JW Player — In case FLV Embed doesn't work

Yahoo Media Player — MP3 player with selectable playlist

Misc:

Weather Widget — puts local temperature in sidebar

WP Forecast — puts full weather info & forecast in sidebar

Bookmark — sidebar link so people can bookmark your site

Random Ads — places random ads in sidebar

Let It Snow —  puts snowflakes on screen

Theme Switcher Reloaded— lets reader select theme

WP-chgFontSize — lets reader change size of text

qTranslate — lets readers select between languages

ieSpell — not an actual plugin but an excellent spell-checker for IE

A big stash of plugins is here.
 

Stopping Plugin Updates

I've seen a few cases where a plugin stopped working after an 'automatic' update'.  'Broken Link Checker' is a perfect example.  Worked fine for years, hit version 0.9 and bam!  Stopped detecting broken links.

The 'trick' is to raise the version number of the last good version so WordPress will compare the two and figure you have the most recent.  In the case of 'Broken Link Checker', I merely changed it from '0.8.1' to '2.8.1' and that did it.

Open the Plugin Editor, select the plugin from the drop-down menu and hit 'Select'.  If you don't see a 'Version' number near the top of the page, try another from the sidebar.