Win95 with shell update up to Windows Me and 2000 had the full trident engine (same as IE 3-5.5) in the Shell (Active Desktop, Explorer bars, etc.). Windows ME/2000 can play audio and video previews in the side bar (all HTML based).

Also WinXP used a forked Trident engine with some removed features for "Software" dialog and various other features (Windows Help, etc).