CD burning

Windows, free

• based on cdrtools
  • the vast majority of open-source tools (Infrarecorder, etc)
• based on XP or Vista's internal burning routines (hardware support is definitely not limitless, specific list here) [also, XP'S INTERNAL BURNING DOESN'T SUPPORT DVDs, but Vista's does)
  • ISORecorder
• CDBurnerXP
• ImgBurn
• more
• not prima facie free, but may be effectively nearly free
  • Nero has a 15-day free trial. If you happen to have a bajillion machines laying around, and tend to re-image them frequently, this may make it effectively free forever.

ISO manipulation

Windows, free

• 7-zip — extraction only
• folder2iso
• infrarecorder (while designed as a full-fledged app, it can be used just for creating ISOs as well)
• more