The Ultimate Indie Game Developer Resource List

[Rio]

Gunz with glasses? No way! D:

Added:
Open Game Art - FREE/open source 2D, 3D art and music; check each license for details just in case, breakdown found here.
Artisteer - automatically create templates for your the most popular CMS sites; $129.95 standard edition
Avangate

Added 4/26:
Dungeon Demon (Rusty Axe) - map editor; $29.99 with free upgrades forever or FREE using TrialPay
International Music Score Library Project - public domain music sheets for US & CAN (EU residents must check); MP3 audio, parts, and full score may be included

[Rio]

Added more:
Divine - turn your PSD to a Wordpress theme; FREE (beta testing going on now)
Crowd Spring - custom logo design, web design, and writing services. Services start at $200 and up.
KalleGraphics Freebie - FREE for commercial use; Alpha Ruler and Kilogram
Font Squirrel - FREE fonts for commercial use; must register
eljbris - FREE fonts for commercial use but extended license needed for embedding or distributing in software apps or hardware devices
Impallari - FREE fonts for commercial use; all fonts under Open Font License
My Fonts - over 62,000 fonts from 800 foundries; prices range from $15 and up; FREE fonts require registration
Trial Pay - place targeted promotions around your game or software; use offer-based payments, dealspot, or direct payments
Super Rewards - monetize your apps and games
BidSystem Ad Marketplace - used for Super Rewards, an in-game monetizing and ad system

More free fonts to be listed later today or tomorrow.

[Rio]

More links!

DLsite - Japanese-English download software portal; mainly VNs !!Adult Site!!
iGame Radio - podcast reviews
Developer Conference (UK)

Also added a new section under Game Building - Finishing:
Backup Your Work!
Acronis Backup & Recovery - auto-backup software $74 and up
Assembla - online storage ranging in price from $9/mo - $100/mo
Crash Plan - range from FREE for personal use to PRO edition for business use ($349.95 and up)
Drop BOx - FREE for 2GB of online storage space OR $9.99/mo for 50GB OR $19.99/mo for 100GB
GitHub - FREE for open source with unlimited space OR pay monthly ranging from $7/mo - $200/mo
iDrive - FREE online storage for 5GB space OR for more space, subscribe monthly starting at $4.95/mo and up
Mozy PRO - Desktop License is $3.95/mo + $0.50/GB per month OR Server License at $6.95/mo + $0.50/GB per month
SyncBackPro - auto-backup software ranging from FREEWARE to SE ($34.95) and PRO ($54.95) editions

[Lucifer]

Sunburn Engine for XNA framework, its the visual part of that engine that stands out (lighting and shading), but it also contains collision testing and some other things.

[butternut]

One more for fonts: dafont.com
Fonts may have been repeated in all other sites, but take a look.

[Rio]

Thanks for the suggestions you guys! I'll list them up when I can later today.

[Rio]

Game Developer Magazine - tends to cover more popular indie titles
Game Dev
Indie Games: The Web Blog
Gamasutra
Indie Pub Games
DIY Gamer

8-bit Funding - indie developer run funding for indie developers

Bit Bucket - price range from FREE unlimited private repository for up to 5 users up to $80/mo for unlimited users; DVCS for Mercurial

Inkscape - open source vector graphics software
Synfig Studio - FREE open source 2D animation software
MyPaint - open source painting program

as3sfxr - open source, in-browser sound effect generator for games; based on sfxr
sfxr - FREE sound generating software
bfxr - in-browser sound effect generator; based on sfxr

gDEBugger - OpenGL and OpenCL debugger, profiler, and memory analyzer; available for Windows, Mac and Linux

Video Game Name Generator

DaFont - Freeware, shareware, demo versions or public domain fonts; please check each font's license before use

POP & IMAP Email
Gmail - FREE
Opera Mail - FREE add-on to Opera browser
Outlook Express - comes with Windows OS
Postbox Inc - $39.95 USD and up; sale price $29.95+
Thunderbird - FREE

Engines
DizzyAGE - FREE; PC only; adventure-style game maker
Adventure Game Studio - FREE point-and-click adventure game engine
Wintermute Engine - FREE point-and-click adventure game engine; can create 2D or 2.5D games
*UPDATED* Flash - $699 alone; may be cheaper if getting bundled editions; also check out Flash Platform Runtimes
Flash Develop - FREE open source source code editor
The Games Factory (Click Team) - $59 USD
Multimedia Fusion 2 (Click Team) - Regular and Dev version available for $119 or $369USD respectively
Cocos2D - FREE 2D iPhone game engine
Sparrow - open source framework for iOS game development
Construct - FREE open source 2D game creator
Panda 3D - FREE 3D game engine
Ethanon Engine - FREE 2D game development tool
Love 2D - FREE, open source framework using Lua; works on Windows, Mac OS and Linux
Sunburn Game Engine - royalty-free XNA engine; price range from $150 USD for indies up to $1000 USD for Studio Edition

Game Libraries
Box 2D - open source physics engine; 2D
Bullet Physics Library - FREE 3D game multiphysics library
FlashPunk - FREE ActionScript 3 library for 2D Flash games
Flixel - open source game-making library
Lightweight Java Game Library - FREE and open source
Open Dynamics Engine (ODE) - open source library for stimulating rigid body dynamics
Slick 2D - FREE and open source; based on LJGL

There was a comment on Reddit regarding the neutrality/impartiality of the engine list. If that person happens to read the rest of this thread then my answer to that is this:
This list, as the title says is a resource. No one way, service, or tool is the right one for everyone. Everyone's experience is also different and to limit the list to those that I (or anyone else) would only use would defeat the whole purpose of the list. If you really like a certain software, tool, or service - then by all means, feel free to recommend what you like here or elsewhere. In the meantime, I'll leave it to each individual to decide for themselves what to use or not use.

xelanoimis over at the IndieGamer Dev Forum has requested that I split the engines per generic or specialized use. I may do this when the list becomes longer (i.e. after I look through the list of game engines he linked to O_O). For now, everything will remain in alphabetical order. As always, any suggestions, recommendations and so on will be very much appreciated.

[DadaAndKids]

This thread is nice resource.

[Rio]

Thanks! Glad you like it. If you have any sites to recommend that I missed, I'd be really grateful.
Similarly, you may like this as well: Massive Online Drawing Tutorials List.

[Rio]

Serendipity - FREE php-powered blog/CMS using BSD license
Habari - open source blog using Apache license

Topleka Voice Pack - FREE for commercial projects as long as you credit toplekaNET and link back to site.

File/HDD Protection
Blancco File Shredder - spot shredding in your HDD; $38.51sUSD
CyberScrub cyberCide - full drive wipe; $29.95USD
Paragon Disk Wiper - full drive wipe; $29.95USD Personal & $149.95USD Professional
Killdisk Professional - full drive wipe; $49.95USD (Win) or $59.95USD Suite

Syncplicity - prices range from FREE to $45/mo Business Edition

YouSentIt - file sharing service; prices range from FREE to $14.99/mo Pro Plus (Corporate available but runs in $1000's)

Luxi-Sans - FREE just as long as license notice is included
Franchise Bold - FREE for commercial use
Surface - FREE for commercial use; Medium weight only
Triskweline - FREE font suited for text editors and programming environments
PT Sans - FREE for commercial use
FontShop Free Fonts - FREE fonts for commercial use; 5 difrerent fonts listed
Mr Jones Book - FREE for commercial use; must register; Mr Jones Book and Mr Jones Book Italic only
Digitica - FREE for commercial use
Cantarell - FREE for commercial use
Exus Pilot - FREE for commercial use
Orbitron - FREE for commercial use
Ripe - FREE for commercial use
Keeparty - FREE for commercial use
LOT - FREE for commercial use
Merge - FREE for commercial use
Inconsolata - FREE open font licensed; great for programming
Fell Types - FREE for commercial use; medievel fonts
Quicksand - FREE for commercial use
Agrafa Hairline - FREE for commercial use; must register
Megalopolis Extra - FREE for commercial use
Sensation - FREEWARE

RPG JS - create a 2D RPG playable by browser using JS Framework

Playism - indie game funding, localization and publishing service (Japanese ONLY for now - ENglish version 2011 3rd Quarter)