So, this is sort of inspired by the pirated-software discussion. It occurred to me that many of the (very expensive) software packages listed actually have fairly passable alternatives. I've been using several of these instead of InDesign for years while making websites using only text-file editors and rendering using open-source solutions, and others are probably in the same boat. Instead of pirating software (especially if one is just starting out),it may be better to use some of these packages.

For my contribution, I've separated the list by category, but the categories aren't definitive - everyone will probably have different needs based on their own work / practice. Open-source software (as opposed to merely 'free' software) is starred.

2D CAD
- *QCAD community edition: http://www.qcad.org/qcad_downloads.html
- *PythonCAD - "it's rudimentary", but it's also written in Python, which is a handy scripting language used by a lot of programs, so maybe it can interface well: http://courira.ca/en/2010/04/pythoncad-open-source-2d-cad-software-part-1
- CADEMIA: http://www.cademia.org/frontend/index.php?sub=29

3D CAD/modeling
- Sketchup: http://sketchup.google.com/
- *Blender3D: http://www.blender.org/
- *BRL-CAD: http://brlcad.org/

Other assorted modeling/information software
- Google Earth: http://earth.google.com/

BIM
- BIM for Rhino - not really free since you need Rhino, but whatev', it's interesting (also, I can't tell if the software itself is free): http://www.rhinobim.com/
- Green Building Markup Language - not really BIM, but a helpful open file format that could be used as the basis of some kind of BIM interface with an open-source (or otherwise) modeling software: http://www.gbxml.org/

Building analysis software
- there are a few floating around, but I can't remember the names! Lighting and stuff like that - perhaps someone else has a better list.

Rendering software
- *PoVRay: http://www.povray.org/
- *YAFray: http://www.yafaray.org/
- Kerkythea: http://www.kerkythea.net/joomla/

Raster graphics
- *GIMP: http://www.gimp.org/
- *GIMPshop - an extension for the Gimp that makes the interface more Photoshop-like: http://www.gimpshop.com/

Vector graphics
- *Inkscape: http://www.inkscape.org/

Layouts
- *Scribus: http://www.scribus.net/canvas/Scribus
- *OpenOffice also has a 'layout' portion of the software, see below

Web design
- Kompozer: http://www.kompozer.net/

Project management software:
- *OpenProj: http://openproj.org/openproj
- *Web2Project: http://web2project.net/
- *Taskjuggler: http://www.taskjuggler.org/
- *Onepoint: http://sourceforge.net/projects/opproject/


General office software
- *OpenOffice: http://www.openoffice.org/
- *Phoenix (e-mail, if you don't want to rely on 'the cloud'): http://phxmail.sourceforge.net/

Other helpful software
- PDF conversion - it's not free for commercial use, but Ghostscript has been really helpful for me, although accurate EPS conversion requires a charge: http://pages.cs.wisc.edu/~ghost/
- *Operating system: there are a zillion flavors of Linux, take your pick

There seems to be a whole lot of software out there that is also free for personal use, but not for commercial use; with a few exceptions I've left these off the list, but they're usually fairly affordable.

The long-term goal of a community resource like this, in my opinion, should be to take charge of our own software future, rather than having functionality automatically given to us by companies that charge tons of money for the privilege (here's looking at you, Autodesk)*. As it is, there are some noticeable holes in functionality (BIM, color management, 3D-CAD that has good control over plotted output, interface issues), but I think that this is in part because architects are not really part of the conversation (it's mostly Internet tech-geeks). To start the process, it could be helpful to figure out what sort of holes need to be plugged before an office can functionally work from open-source solutions (or have better integration from a wider variety of programs, rather than being stuck in the somewhat linear AutoCAD-Ecotect-Revit-InDesign ecosystem). Developing an effective workflow between programs could also be part of this process.

* - Not that I'm a rabid anti-closed-source zealot or anything; proprietary software is often worth the money, especially if you need to do something very specific and technical. However, for the majority of architects, we'd probably benefit more if we had at least some of the functionality spread across multiple programs that didn't cost so much and were alterable to our own ends.