Flutterby™! :

And http://www.98lite.net/ explores what you can do when you decouple Windows 98 and Internet Explorer:

These possibilities are realised by implanting the leaner and faster Explorer shell from Windows95 onto the improved core of Windows98. You keep all the great Windows98 improvements to the hardware support, drivers, memory management, Fat32 and improved networking, but the Explorer95 interface is considerably faster and consumes fewer computer resources.