I expected Gizmo Drive (free) to be something like WinCDEmu, which sits quietly in the background and allows you to mount images as virtual CD/DVD drives. In the end, that's part of what Gizmo Drive turned out to be--but before that I was taken for a ride to a little world which I'm going to call Gizmo Land. Installing Gizmo Drive requires that you download the Gizmo software suite, which includes Gizmo Central (or Manager once it's installed) Gizmo Drive, Gizmo Script, Gizmo Database. Gizmo Editor, and Gizmo Hasher. There's also a Gizmo toolbar that sits in the system tray and provides shortcut access to programs (not just Gizmo modules). It's only 8MB in total, and some of it's pretty handy--but this is about Gizmo Drive.
Once I had Gizmo Central/Manager and Gizmo Drive installed, all I needed to do was right-click an ISO, BIN, CUE, or NRG file. Sure enough, there were the mount and burn options. When you mount an image using Gizmo Drive, you can bypass the dialog which allows you to tweak settings such as the drive letter, and use the next available drive letter by pressing the control key. It's nice to have both options, though I wish bypassing the dialog was the default.
The option to burn an image file to disc puts the program one up on the aforementioned WinCDEmu which only mounts such files. To burn an image you must install the KB932716 IMAPI (Image Mastering API 2.0) Windows Update if you haven't already and Gizmo will tell you if you haven't. Gizmo Drive worked fine in my tests, so if you don't mind the side trip through Gizmo Land, it's a great little image-handling extension for Windows.