The nice thing about the majority of these free tools is that no account creation is required.
Button Factory - http://dabuttonfactory.com/
Create buttons online. It's free and has nice 2.0 buttons!
Drawter - http://drawter.com/
Whoever made this deserves an award. Quite intuitive free tool that allows you to draw your website and generates the code for it.
WhosAmungUs - http://whos.amung.us/
Web site tracking widget including displaying visitor info on a map.
Sosius - http://sosius.com/Haven't tried this personally (yet) but it looks cool. It's an online workspace.
Bubbl.us - http://www.bubbl.us/
Cool mind mapping online.
Buttonator - http://www.buttonator.com/
Modern styles for making buttons.
Charts - http://charts.hohli.com/
Great for making quick charts.
Online Code Converter - http://code.cside.com/3rdpage/us/javaUnicode/converter.html
Convert character codes.
MorgueFile - http://www.morguefile.com/
Stock photos even for commercial use (read the 'license').
Wufoo - http://wufoo.com/
Create online forms for every occassion you can imagine. Versatile and good for inspiration.
280 Slides - http://280slides.com/Editor/
It's basically Powerpoint online. Free and easy.
Color Scheme Designer 3 - http://colorschemedesigner.com/
Design colour schemes online. (Nice interface)
COLOURlovers - http://www.colourlovers.com/palettes
This is an interesting site that not only provides colour schemes but also schemes based on patterns.
Pattern Tap - http://patterntap.com/
Awesome place for inspiration. You can view the different looks of 404 Pages, Audio, Breadcrumbs, Borders, Comments, Contact etc...
Kuler - http://kuler.adobe.com/#themes/rating?time=30
Colour schemes you can contribute and create.
IzzyMenu (Builder) - http://www.izzymenu.com/
Comprehensive online menu builder that doesn't require an account.
Wirenode - http://www.wirenode.com/
This is an "ok" site. It provides a fast way, visual way of creating a site for mobile devices.
doTemplate - http://www.dotemplate.com/
This is the ultimate for lazy visual people. Customize the templates they have online and the templates are actually good!
Web Graphics Maker - http://en.web-graphics-maker.com/
Make backgrounds, lines, and bullets online. Includes transparency on png's.
Bradicon! - http://ico.bradleygill.com/advanced.php
Turn images in to icons.
Text to PNG - http://www.text2png.com/
Interesting concept. Converts plain text into a png. You can either use hosted (free) or grab the source for yourself (requires php).
Iconspedia - http://www.iconspedia.com/
Ok, not a tool but wicked Web 2.0 style icons/buttons/images.
Fresh Badge - http://www.freshbadge.com/
An ok site that generates badges.
Loading GIF Generator - http://www.webscriptlab.com/index.php
Good idea! Create animations to use as a 'loading' message.
Dynamic Drive Button Maker Online - http://tools.dynamicdrive.com/button/
Creates small buttons (eg, rss, xhtml etc...)
Timelines - http://www.mytimelines.net/
Create cut and paste timelines from any feed.
Wordle - http://www.wordle.net/
Create tag clouds.
Iaza - http://iaza.com/
Vast assortment of image manipulation capabilities online.
LogoMaker - http://logomaker.com/
Cool creative customizable icons. Create the logo and link to it for free or download it for a price.
FotoFlexer - http://fotoflexer.com/
Basic image manipulation online.
Maya - http://www.stockfreephoto.com/
Online image manipulation. You can also download this and place it on your own site for free. (PHP)
Pixenate - http://pixenate.com/
Another free online image manipulation site.
Online Button Maker - http://www.advancewebsoft.com/free-oscommerce-cre-loaded-zen-cart-oscmax-button-generator-p.html
Pretty good button generator.
P&P World Map - http://edit.freemap.jp/en/trial_version/edit/world
Allows you to customize the look of a map and dowload it. Pretty cool!
Big Huge Labs - http://bighugelabs.com/
Show off your pics from Flickr or Facebook. Create calendars, motivation posters, badges and more.
CSS Round Corner Generator - http://www.roundedcornr.com/ Pretty cool generator!
Cool Text - http://cooltext.com/
Logo Generator - http://www.logogenerator.com/
Excellent online logo generator and it's free!