Reaper Quite possibly the best DAW for computer music making in the world. Really. You owe it to yourself to give it a try.
Scribus The best and, possibly, the only Open Source DTP software in the world. I used it for the re-release of our Palindrome CD. Totally professional application. Fabulous.
Portable Freeware Another site listing portable software – this time, all freeware (as opposed to open source) that can be run directly from a USB stick. Some great stuff here.
Portable Apps Great site listing portable software application
Inkscape Another Open Source treasure, this is seriously good now it has reached version 0.47. It is better – in many respects – than Illustrator, the industry standard.