Open Source Graphic Programs
Mauricio Duque at Snap2Objects.com has an amazing list of 40 open source graphic programs that are definitely worth a look if you are involved with Web design, or any design for that matter. The post includes project names, screenshots, development status and the supported platforms. While some of the programs listed have a restricted license use, most allow for commercial use which is good if you're bootstrapping your fledgling design business.
The tools are broken down into categories; editors (Scribus), graphics conversion (Xpdf), presentation (MinDia), modeling (White Dune), rendering (Grass GIS), viewers (Endeavour Mark II). Now before you run off and start shouting that Gimp wasn't on the list, check out Snap2objects 45 best freeware design programs.