Windows/Linux: ImgBurn is the most popular CD and DVD burning tool among Lifehacker readers, and with the newly released version 2.5, it's even better.
You can hit up the full changelog for an in-depth look at the changes, but the biggest feature update is an Advanced mode that gives you more fine-grained control over the layout of files on the disc. You can now rename files, add new folders, and more, directly inside ImgBurn. (As the changelog puts it, "you're no longer limited to burning an existing folder structure on your hard disc as-is.")
Apart from that, you'll notice all kinds of added support for file types and error handling, slightly tweaked or improved features, and a handful of fixed bugs. We already love ImgBurn as is, and while this update isn't boasting any terribly sexy new features, it's great to see that the freeware favourite is still under active development.
ImgBurn is freeware, works on Windows and Linux (using Wine).